llvmpipe: implement scissor testing
[mesa.git] / src / gallium / drivers / llvmpipe / lp_state_fs.c
index b00be0cc32af5635c1a40028be93457397c3587e..d12d3f6091aeb10ab56d6744daba541128766bc1 100644 (file)
@@ -58,6 +58,7 @@
  * @author Jose Fonseca <jfonseca@vmware.com>
  */
 
+#include <limits.h>
 #include "pipe/p_defines.h"
 #include "util/u_memory.h"
 #include "util/u_format.h"
 #include "lp_bld_debug.h"
 #include "lp_screen.h"
 #include "lp_context.h"
+#include "lp_buffer.h"
+#include "lp_setup.h"
 #include "lp_state.h"
-#include "lp_quad.h"
 #include "lp_tex_sample.h"
+#include "lp_debug.h"
 
 
 static const unsigned char quad_offset_x[4] = {0, 1, 0, 1};
@@ -147,6 +150,20 @@ generate_depth(LLVMBuilderRef builder,
    format_desc = util_format_description(key->zsbuf_format);
    assert(format_desc);
 
+   /*
+    * Depths are expected to be between 0 and 1, even if they are stored in
+    * floats. Setting these bits here will ensure that the lp_build_conv() call
+    * below won't try to unnecessarily clamp the incoming values.
+    */
+   if(src_type.floating) {
+      src_type.sign = FALSE;
+      src_type.norm = TRUE;
+   }
+   else {
+      assert(!src_type.sign);
+      assert(src_type.norm);
+   }
+
    /* Pick the depth type. */
    dst_type = lp_depth_type(format_desc, src_type.width*src_type.length);
 
@@ -154,14 +171,11 @@ generate_depth(LLVMBuilderRef builder,
    assert(dst_type.width == src_type.width);
    assert(dst_type.length == src_type.length);
 
-#if 1
-   src = lp_build_clamped_float_to_unsigned_norm(builder,
-                                                 src_type,
-                                                 dst_type.width,
-                                                 src);
-#else
    lp_build_conv(builder, src_type, dst_type, &src, 1, &src, 1);
-#endif
+
+   dst_ptr = LLVMBuildBitCast(builder,
+                              dst_ptr,
+                              LLVMPointerType(lp_build_vec_type(dst_type), 0), "");
 
    lp_build_depth_test(builder,
                        &key->depth,
@@ -173,8 +187,171 @@ generate_depth(LLVMBuilderRef builder,
 }
 
 
+/**
+ * Generate the code to do inside/outside triangle testing for the
+ * four pixels in a 2x2 quad.  This will set the four elements of the
+ * quad mask vector to 0 or ~0.
+ * \param i  which quad of the quad group to test, in [0,3]
+ */
+static void
+generate_tri_edge_mask(LLVMBuilderRef builder,
+                       unsigned i,
+                       LLVMValueRef *mask,      /* ivec4, out */
+                       LLVMValueRef c0,         /* int32 */
+                       LLVMValueRef c1,         /* int32 */
+                       LLVMValueRef c2,         /* int32 */
+                       LLVMValueRef step0_ptr,  /* ivec4 */
+                       LLVMValueRef step1_ptr,  /* ivec4 */
+                       LLVMValueRef step2_ptr)  /* ivec4 */
+{
+#define OPTIMIZE_IN_OUT_TEST 0
+#if OPTIMIZE_IN_OUT_TEST
+   struct lp_build_if_state ifctx;
+   LLVMValueRef not_draw_all;
+#endif
+   struct lp_build_flow_context *flow;
+   struct lp_type i32_type;
+   LLVMTypeRef i32vec4_type, mask_type;
+   LLVMValueRef c0_vec, c1_vec, c2_vec;
+   LLVMValueRef in_out_mask;
+
+   assert(i < 4);
+   
+   /* int32 vector type */
+   memset(&i32_type, 0, sizeof i32_type);
+   i32_type.floating = FALSE; /* values are integers */
+   i32_type.sign = TRUE;      /* values are signed */
+   i32_type.norm = FALSE;     /* values are not normalized */
+   i32_type.width = 32;       /* 32-bit int values */
+   i32_type.length = 4;       /* 4 elements per vector */
+
+   i32vec4_type = lp_build_int32_vec4_type();
+
+   mask_type = LLVMIntType(32 * 4);
+
+   /*
+    * Use a conditional here to do detailed pixel in/out testing.
+    * We only have to do this if c0 != INT_MIN.
+    */
+   flow = lp_build_flow_create(builder);
+   lp_build_flow_scope_begin(flow);
+
+   {
+#if OPTIMIZE_IN_OUT_TEST
+      /* not_draw_all = (c0 != INT_MIN) */
+      not_draw_all = LLVMBuildICmp(builder,
+                                   LLVMIntNE,
+                                   c0,
+                                   LLVMConstInt(LLVMInt32Type(), INT_MIN, 0),
+                                   "");
+
+      in_out_mask = lp_build_int_const_scalar(i32_type, ~0);
+
+
+      lp_build_flow_scope_declare(flow, &in_out_mask);
+
+      /* if (not_draw_all) {... */
+      lp_build_if(&ifctx, flow, builder, not_draw_all);
+#endif
+      {
+         LLVMValueRef step0_vec, step1_vec, step2_vec;
+         LLVMValueRef m0_vec, m1_vec, m2_vec;
+         LLVMValueRef index, m;
+
+         /* c0_vec = {c0, c0, c0, c0}
+          * Note that we emit this code four times but LLVM optimizes away
+          * three instances of it.
+          */
+         c0_vec = lp_build_broadcast(builder, i32vec4_type, c0);
+         c1_vec = lp_build_broadcast(builder, i32vec4_type, c1);
+         c2_vec = lp_build_broadcast(builder, i32vec4_type, c2);
+         lp_build_name(c0_vec, "edgeconst0vec");
+         lp_build_name(c1_vec, "edgeconst1vec");
+         lp_build_name(c2_vec, "edgeconst2vec");
+
+         /* load step0vec, step1, step2 vec from memory */
+         index = LLVMConstInt(LLVMInt32Type(), i, 0);
+         step0_vec = LLVMBuildLoad(builder, LLVMBuildGEP(builder, step0_ptr, &index, 1, ""), "");
+         step1_vec = LLVMBuildLoad(builder, LLVMBuildGEP(builder, step1_ptr, &index, 1, ""), "");
+         step2_vec = LLVMBuildLoad(builder, LLVMBuildGEP(builder, step2_ptr, &index, 1, ""), "");
+         lp_build_name(step0_vec, "step0vec");
+         lp_build_name(step1_vec, "step1vec");
+         lp_build_name(step2_vec, "step2vec");
+
+         /* m0_vec = step0_ptr[i] > c0_vec */
+         m0_vec = lp_build_compare(builder, i32_type, PIPE_FUNC_GREATER, step0_vec, c0_vec);
+         m1_vec = lp_build_compare(builder, i32_type, PIPE_FUNC_GREATER, step1_vec, c1_vec);
+         m2_vec = lp_build_compare(builder, i32_type, PIPE_FUNC_GREATER, step2_vec, c2_vec);
+
+         /* in_out_mask = m0_vec & m1_vec & m2_vec */
+         m = LLVMBuildAnd(builder, m0_vec, m1_vec, "");
+         in_out_mask = LLVMBuildAnd(builder, m, m2_vec, "");
+         lp_build_name(in_out_mask, "inoutmaskvec");
+      }
+#if OPTIMIZE_IN_OUT_TEST
+      lp_build_endif(&ifctx);
+#endif
+
+   }
+   lp_build_flow_scope_end(flow);
+   lp_build_flow_destroy(flow);
+
+   /* This is the initial alive/dead pixel mask for a quad of four pixels.
+    * It's an int[4] vector with each word set to 0 or ~0.
+    * Words will get cleared when pixels faile the Z test, etc.
+    */
+   *mask = in_out_mask;
+}
+
+
+static LLVMValueRef
+generate_scissor_test(LLVMBuilderRef builder,
+                      LLVMValueRef context_ptr,
+                      const struct lp_build_interp_soa_context *interp,
+                      struct lp_type type)
+{
+   LLVMTypeRef vec_type = lp_build_vec_type(type);
+   LLVMValueRef xpos = interp->pos[0], ypos = interp->pos[1];
+   LLVMValueRef xmin, ymin, xmax, ymax;
+   LLVMValueRef m0, m1, m2, m3, m;
+
+   /* xpos, ypos contain the window coords for the four pixels in the quad */
+   assert(xpos);
+   assert(ypos);
+
+   /* get the current scissor bounds, convert to vectors */
+   xmin = lp_jit_context_scissor_xmin_value(builder, context_ptr);
+   xmin = lp_build_broadcast(builder, vec_type, xmin);
+
+   ymin = lp_jit_context_scissor_ymin_value(builder, context_ptr);
+   ymin = lp_build_broadcast(builder, vec_type, ymin);
+
+   xmax = lp_jit_context_scissor_xmax_value(builder, context_ptr);
+   xmax = lp_build_broadcast(builder, vec_type, xmax);
+
+   ymax = lp_jit_context_scissor_ymax_value(builder, context_ptr);
+   ymax = lp_build_broadcast(builder, vec_type, ymax);
+
+   /* compare the fragment's position coordinates against the scissor bounds */
+   m0 = lp_build_compare(builder, type, PIPE_FUNC_GEQUAL, xpos, xmin);
+   m1 = lp_build_compare(builder, type, PIPE_FUNC_GEQUAL, ypos, ymin);
+   m2 = lp_build_compare(builder, type, PIPE_FUNC_LESS, xpos, xmax);
+   m3 = lp_build_compare(builder, type, PIPE_FUNC_LESS, ypos, ymax);
+
+   /* AND all the masks together */
+   m = LLVMBuildAnd(builder, m0, m1, "");
+   m = LLVMBuildAnd(builder, m, m2, "");
+   m = LLVMBuildAnd(builder, m, m3, "");
+
+   lp_build_name(m, "scissormask");
+
+   return m;
+}
+
+
 /**
  * Generate the fragment shader, depth/stencil test, and alpha tests.
+ * \param i  which quad in the tile, in range [0,3]
  */
 static void
 generate_fs(struct llvmpipe_context *lp,
@@ -187,8 +364,14 @@ generate_fs(struct llvmpipe_context *lp,
             const struct lp_build_interp_soa_context *interp,
             struct lp_build_sampler_soa *sampler,
             LLVMValueRef *pmask,
-            LLVMValueRef *color,
-            LLVMValueRef depth_ptr)
+            LLVMValueRef (*color)[4],
+            LLVMValueRef depth_ptr,
+            LLVMValueRef c0,
+            LLVMValueRef c1,
+            LLVMValueRef c2,
+            LLVMValueRef step0_ptr,
+            LLVMValueRef step1_ptr,
+            LLVMValueRef step2_ptr)
 {
    const struct tgsi_token *tokens = shader->base.tokens;
    LLVMTypeRef elem_type;
@@ -202,6 +385,9 @@ generate_fs(struct llvmpipe_context *lp,
    boolean early_depth_test;
    unsigned attrib;
    unsigned chan;
+   unsigned cbuf;
+
+   assert(i < 4);
 
    elem_type = lp_build_elem_type(type);
    vec_type = lp_build_vec_type(type);
@@ -216,14 +402,27 @@ generate_fs(struct llvmpipe_context *lp,
    lp_build_flow_scope_begin(flow);
 
    /* Declare the color and z variables */
-   for(chan = 0; chan < NUM_CHANNELS; ++chan) {
-      color[chan] = LLVMGetUndef(vec_type);
-      lp_build_flow_scope_declare(flow, &color[chan]);
+   for(cbuf = 0; cbuf < key->nr_cbufs; cbuf++) {
+      for(chan = 0; chan < NUM_CHANNELS; ++chan) {
+        color[cbuf][chan] = LLVMGetUndef(vec_type);
+        lp_build_flow_scope_declare(flow, &color[cbuf][chan]);
+      }
    }
    lp_build_flow_scope_declare(flow, &z);
 
+   /* do triangle edge testing */
+   generate_tri_edge_mask(builder, i, pmask,
+                          c0, c1, c2, step0_ptr, step1_ptr, step2_ptr);
+
+   /* 'mask' will control execution based on quad's pixel alive/killed state */
    lp_build_mask_begin(&mask, flow, type, *pmask);
 
+   if (key->scissor) {
+      LLVMValueRef smask =
+         generate_scissor_test(builder, context_ptr, interp, type);
+      lp_build_mask_update(&mask, smask);
+   }
+
    early_depth_test =
       key->depth.enabled &&
       !key->alpha.enabled &&
@@ -253,6 +452,7 @@ generate_fs(struct llvmpipe_context *lp,
 
                   /* Alpha test */
                   /* XXX: should the alpha reference value be passed separately? */
+                 /* XXX: should only test the final assignment to alpha */
                   if(cbuf == 0 && chan == 3) {
                      LLVMValueRef alpha = outputs[attrib][chan];
                      LLVMValueRef alpha_ref_value;
@@ -262,9 +462,7 @@ generate_fs(struct llvmpipe_context *lp,
                                          &mask, alpha, alpha_ref_value);
                   }
 
-                  if(cbuf == 0)
-                     color[chan] = outputs[attrib][chan];
-
+                 color[cbuf][chan] = outputs[attrib][chan];
                   break;
                }
 
@@ -319,6 +517,8 @@ generate_blend(const struct pipe_blend_state *blend,
    lp_build_context_init(&bld, builder, type);
 
    flow = lp_build_flow_create(builder);
+
+   /* we'll use this mask context to skip blending if all pixels are dead */
    lp_build_mask_begin(&mask_ctx, flow, type, mask);
 
    vec_type = lp_build_vec_type(type);
@@ -356,14 +556,17 @@ generate_blend(const struct pipe_blend_state *blend,
 
 /**
  * Generate the runtime callable function for the whole fragment pipeline.
+ * Note that the function which we generate operates on a block of 16
+ * pixels at at time.  The block contains 2x2 quads.  Each quad contains
+ * 2x2 pixels.
  */
-static struct lp_fragment_shader_variant *
+static void
 generate_fragment(struct llvmpipe_context *lp,
                   struct lp_fragment_shader *shader,
-                  const struct lp_fragment_shader_variant_key *key)
+                  struct lp_fragment_shader_variant *variant)
 {
    struct llvmpipe_screen *screen = llvmpipe_screen(lp->pipe.screen);
-   struct lp_fragment_shader_variant *variant;
+   const struct lp_fragment_shader_variant_key *key = &variant->key;
    struct lp_type fs_type;
    struct lp_type blend_type;
    LLVMTypeRef fs_elem_type;
@@ -371,17 +574,18 @@ generate_fragment(struct llvmpipe_context *lp,
    LLVMTypeRef fs_int_vec_type;
    LLVMTypeRef blend_vec_type;
    LLVMTypeRef blend_int_vec_type;
-   LLVMTypeRef arg_types[9];
+   LLVMTypeRef arg_types[14];
    LLVMTypeRef func_type;
+   LLVMTypeRef int32_vec4_type = lp_build_int32_vec4_type();
    LLVMValueRef context_ptr;
    LLVMValueRef x;
    LLVMValueRef y;
    LLVMValueRef a0_ptr;
    LLVMValueRef dadx_ptr;
    LLVMValueRef dady_ptr;
-   LLVMValueRef mask_ptr;
-   LLVMValueRef color_ptr;
+   LLVMValueRef color_ptr_ptr;
    LLVMValueRef depth_ptr;
+   LLVMValueRef c0, c1, c2, step0_ptr, step1_ptr, step2_ptr;
    LLVMBasicBlockRef block;
    LLVMBuilderRef builder;
    LLVMValueRef x0;
@@ -389,43 +593,14 @@ generate_fragment(struct llvmpipe_context *lp,
    struct lp_build_sampler_soa *sampler;
    struct lp_build_interp_soa_context interp;
    LLVMValueRef fs_mask[LP_MAX_VECTOR_LENGTH];
-   LLVMValueRef fs_out_color[NUM_CHANNELS][LP_MAX_VECTOR_LENGTH];
+   LLVMValueRef fs_out_color[PIPE_MAX_COLOR_BUFS][NUM_CHANNELS][LP_MAX_VECTOR_LENGTH];
    LLVMValueRef blend_mask;
    LLVMValueRef blend_in_color[NUM_CHANNELS];
    unsigned num_fs;
    unsigned i;
    unsigned chan;
+   unsigned cbuf;
 
-#ifdef DEBUG
-   tgsi_dump(shader->base.tokens, 0);
-   if(key->depth.enabled) {
-      debug_printf("depth.func = %s\n", debug_dump_func(key->depth.func, TRUE));
-      debug_printf("depth.writemask = %u\n", key->depth.writemask);
-   }
-   if(key->alpha.enabled) {
-      debug_printf("alpha.func = %s\n", debug_dump_func(key->alpha.func, TRUE));
-      debug_printf("alpha.ref_value = %f\n", key->alpha.ref_value);
-   }
-   if(key->blend.logicop_enable) {
-      debug_printf("blend.logicop_func = %u\n", key->blend.logicop_func);
-   }
-   else if(key->blend.blend_enable) {
-      debug_printf("blend.rgb_func = %s\n",   debug_dump_blend_func  (key->blend.rgb_func, TRUE));
-      debug_printf("rgb_src_factor = %s\n",   debug_dump_blend_factor(key->blend.rgb_src_factor, TRUE));
-      debug_printf("rgb_dst_factor = %s\n",   debug_dump_blend_factor(key->blend.rgb_dst_factor, TRUE));
-      debug_printf("alpha_func = %s\n",       debug_dump_blend_func  (key->blend.alpha_func, TRUE));
-      debug_printf("alpha_src_factor = %s\n", debug_dump_blend_factor(key->blend.alpha_src_factor, TRUE));
-      debug_printf("alpha_dst_factor = %s\n", debug_dump_blend_factor(key->blend.alpha_dst_factor, TRUE));
-   }
-   debug_printf("blend.colormask = 0x%x\n", key->blend.colormask);
-#endif
-
-   variant = CALLOC_STRUCT(lp_fragment_shader_variant);
-   if(!variant)
-      return NULL;
-
-   variant->shader = shader;
-   memcpy(&variant->key, key, sizeof *key);
 
    /* TODO: actually pick these based on the fs and color buffer
     * characteristics. */
@@ -435,8 +610,8 @@ generate_fragment(struct llvmpipe_context *lp,
    fs_type.sign = TRUE;     /* values are signed */
    fs_type.norm = FALSE;    /* values are not limited to [0,1] or [-1,1] */
    fs_type.width = 32;      /* 32-bit float */
-   fs_type.length = 4;      /* 4 element per vector */
-   num_fs = 4;
+   fs_type.length = 4;      /* 4 elements per vector */
+   num_fs = 4;              /* number of quads per block */
 
    memset(&blend_type, 0, sizeof blend_type);
    blend_type.floating = FALSE; /* values are integers */
@@ -463,14 +638,26 @@ generate_fragment(struct llvmpipe_context *lp,
    arg_types[3] = LLVMPointerType(fs_elem_type, 0);    /* a0 */
    arg_types[4] = LLVMPointerType(fs_elem_type, 0);    /* dadx */
    arg_types[5] = LLVMPointerType(fs_elem_type, 0);    /* dady */
-   arg_types[6] = LLVMPointerType(fs_int_vec_type, 0); /* mask */
-   arg_types[7] = LLVMPointerType(blend_vec_type, 0);  /* color */
-   arg_types[8] = LLVMPointerType(fs_int_vec_type, 0); /* depth */
+   arg_types[6] = LLVMPointerType(LLVMPointerType(blend_vec_type, 0), 0);  /* color */
+   arg_types[7] = LLVMPointerType(fs_int_vec_type, 0); /* depth */
+   arg_types[8] = LLVMInt32Type();                     /* c0 */
+   arg_types[9] = LLVMInt32Type();                    /* c1 */
+   arg_types[10] = LLVMInt32Type();                    /* c2 */
+   /* Note: the step arrays are built as int32[16] but we interpret
+    * them here as int32_vec4[4].
+    */
+   arg_types[11] = LLVMPointerType(int32_vec4_type, 0);/* step0 */
+   arg_types[12] = LLVMPointerType(int32_vec4_type, 0);/* step1 */
+   arg_types[13] = LLVMPointerType(int32_vec4_type, 0);/* step2 */
 
    func_type = LLVMFunctionType(LLVMVoidType(), arg_types, Elements(arg_types), 0);
 
    variant->function = LLVMAddFunction(screen->module, "shader", func_type);
    LLVMSetFunctionCallConv(variant->function, LLVMCCallConv);
+
+   /* XXX: need to propagate noalias down into color param now we are
+    * passing a pointer-to-pointer?
+    */
    for(i = 0; i < Elements(arg_types); ++i)
       if(LLVMGetTypeKind(arg_types[i]) == LLVMPointerTypeKind)
          LLVMAddAttribute(LLVMGetParam(variant->function, i), LLVMNoAliasAttribute);
@@ -481,9 +668,14 @@ generate_fragment(struct llvmpipe_context *lp,
    a0_ptr       = LLVMGetParam(variant->function, 3);
    dadx_ptr     = LLVMGetParam(variant->function, 4);
    dady_ptr     = LLVMGetParam(variant->function, 5);
-   mask_ptr     = LLVMGetParam(variant->function, 6);
-   color_ptr    = LLVMGetParam(variant->function, 7);
-   depth_ptr    = LLVMGetParam(variant->function, 8);
+   color_ptr_ptr = LLVMGetParam(variant->function, 6);
+   depth_ptr    = LLVMGetParam(variant->function, 7);
+   c0           = LLVMGetParam(variant->function, 8);
+   c1           = LLVMGetParam(variant->function, 9);
+   c2           = LLVMGetParam(variant->function, 10);
+   step0_ptr    = LLVMGetParam(variant->function, 11);
+   step1_ptr    = LLVMGetParam(variant->function, 12);
+   step2_ptr    = LLVMGetParam(variant->function, 13);
 
    lp_build_name(context_ptr, "context");
    lp_build_name(x, "x");
@@ -491,9 +683,14 @@ generate_fragment(struct llvmpipe_context *lp,
    lp_build_name(a0_ptr, "a0");
    lp_build_name(dadx_ptr, "dadx");
    lp_build_name(dady_ptr, "dady");
-   lp_build_name(mask_ptr, "mask");
-   lp_build_name(color_ptr, "color");
+   lp_build_name(color_ptr_ptr, "color_ptr");
    lp_build_name(depth_ptr, "depth");
+   lp_build_name(c0, "c0");
+   lp_build_name(c1, "c1");
+   lp_build_name(c2, "c2");
+   lp_build_name(step0_ptr, "step0");
+   lp_build_name(step1_ptr, "step1");
+   lp_build_name(step2_ptr, "step2");
 
    /*
     * Function body
@@ -505,27 +702,26 @@ generate_fragment(struct llvmpipe_context *lp,
 
    generate_pos0(builder, x, y, &x0, &y0);
 
-   lp_build_interp_soa_init(&interp, shader->base.tokens, builder, fs_type,
+   lp_build_interp_soa_init(&interp, 
+                            shader->base.tokens,
+                            key->flatshade,
+                            builder, fs_type,
                             a0_ptr, dadx_ptr, dady_ptr,
-                            x0, y0, 2, 0);
+                            x0, y0);
 
-#if 0
-   /* C texture sampling */
-   sampler = lp_c_sampler_soa_create(context_ptr);
-#else
    /* code generated texture sampling */
    sampler = lp_llvm_sampler_soa_create(key->sampler, context_ptr);
-#endif
 
+   /* loop over quads in the block */
    for(i = 0; i < num_fs; ++i) {
       LLVMValueRef index = LLVMConstInt(LLVMInt32Type(), i, 0);
-      LLVMValueRef out_color[NUM_CHANNELS];
+      LLVMValueRef out_color[PIPE_MAX_COLOR_BUFS][NUM_CHANNELS];
       LLVMValueRef depth_ptr_i;
+      int cbuf;
 
       if(i != 0)
-         lp_build_interp_soa_update(&interp);
+         lp_build_interp_soa_update(&interp, i);
 
-      fs_mask[i] = LLVMBuildLoad(builder, LLVMBuildGEP(builder, mask_ptr, &index, 1, ""), "");
       depth_ptr_i = LLVMBuildGEP(builder, depth_ptr, &index, 1, "");
 
       generate_fs(lp, shader, key,
@@ -535,72 +731,162 @@ generate_fragment(struct llvmpipe_context *lp,
                   i,
                   &interp,
                   sampler,
-                  &fs_mask[i],
+                  &fs_mask[i], /* output */
                   out_color,
-                  depth_ptr_i);
+                  depth_ptr_i,
+                  c0, c1, c2,
+                  step0_ptr, step1_ptr, step2_ptr);
 
-      for(chan = 0; chan < NUM_CHANNELS; ++chan)
-         fs_out_color[chan][i] = out_color[chan];
+      for(cbuf = 0; cbuf < key->nr_cbufs; cbuf++)
+        for(chan = 0; chan < NUM_CHANNELS; ++chan)
+           fs_out_color[cbuf][chan][i] = out_color[cbuf][chan];
    }
 
    sampler->destroy(sampler);
 
-   /* 
-    * Convert the fs's output color and mask to fit to the blending type. 
+   /* Loop over color outputs / color buffers to do blending.
     */
+   for(cbuf = 0; cbuf < key->nr_cbufs; cbuf++) {
+      LLVMValueRef color_ptr;
+      LLVMValueRef index = LLVMConstInt(LLVMInt32Type(), cbuf, 0);
 
-   for(chan = 0; chan < NUM_CHANNELS; ++chan) {
-      lp_build_conv(builder, fs_type, blend_type,
-                    fs_out_color[chan], num_fs,
-                    &blend_in_color[chan], 1);
-      lp_build_name(blend_in_color[chan], "color.%c", "rgba"[chan]);
+      /* 
+       * Convert the fs's output color and mask to fit to the blending type. 
+       */
+      for(chan = 0; chan < NUM_CHANNELS; ++chan) {
+        lp_build_conv(builder, fs_type, blend_type,
+                      fs_out_color[cbuf][chan], num_fs,
+                      &blend_in_color[chan], 1);
+        lp_build_name(blend_in_color[chan], "color%d.%c", cbuf, "rgba"[chan]);
+      }
 
+      lp_build_conv_mask(builder, fs_type, blend_type,
+                        fs_mask, num_fs,
+                        &blend_mask, 1);
+
+      color_ptr = LLVMBuildLoad(builder, 
+                               LLVMBuildGEP(builder, color_ptr_ptr, &index, 1, ""),
+                               "");
+      lp_build_name(color_ptr, "color_ptr%d", cbuf);
+
+      /*
+       * Blending.
+       */
+      generate_blend(&key->blend,
+                    builder,
+                    blend_type,
+                    context_ptr,
+                    blend_mask,
+                    blend_in_color,
+                    color_ptr);
    }
 
-   lp_build_conv_mask(builder, fs_type, blend_type,
-                               fs_mask, num_fs,
-                               &blend_mask, 1);
-
-   /*
-    * Blending.
-    */
-
-   generate_blend(&key->blend,
-                  builder,
-                  blend_type,
-                  context_ptr,
-                  blend_mask,
-                  blend_in_color,
-                  color_ptr);
-
    LLVMBuildRetVoid(builder);
 
    LLVMDisposeBuilder(builder);
 
-   /*
-    * Translate the LLVM IR into machine code.
-    */
 
+   /* Verify the LLVM IR.  If invalid, dump and abort */
+#ifdef DEBUG
    if(LLVMVerifyFunction(variant->function, LLVMPrintMessageAction)) {
-      LLVMDumpValue(variant->function);
+      if (1)
+         LLVMDumpValue(variant->function);
       abort();
    }
+#endif
 
-   LLVMRunFunctionPassManager(screen->pass, variant->function);
+   /* Apply optimizations to LLVM IR */
+   if (1)
+      LLVMRunFunctionPassManager(screen->pass, variant->function);
 
-#ifdef DEBUG
-   LLVMDumpValue(variant->function);
-   debug_printf("\n");
-#endif
+   if (LP_DEBUG & DEBUG_JIT) {
+      /* Print the LLVM IR to stderr */
+      LLVMDumpValue(variant->function);
+      debug_printf("\n");
+   }
 
+   /*
+    * Translate the LLVM IR into machine code.
+    */
    variant->jit_function = (lp_jit_frag_func)LLVMGetPointerToGlobal(screen->engine, variant->function);
 
-#ifdef DEBUG
-   lp_disassemble(variant->jit_function);
-#endif
+   if (LP_DEBUG & DEBUG_ASM)
+      lp_disassemble(variant->jit_function);
 
    variant->next = shader->variants;
    shader->variants = variant;
+}
+
+
+static struct lp_fragment_shader_variant *
+generate_variant(struct llvmpipe_context *lp,
+                 struct lp_fragment_shader *shader,
+                 const struct lp_fragment_shader_variant_key *key)
+{
+   struct lp_fragment_shader_variant *variant;
+
+   if (LP_DEBUG & DEBUG_JIT) {
+      unsigned i;
+
+      tgsi_dump(shader->base.tokens, 0);
+      if(key->depth.enabled) {
+         debug_printf("depth.format = %s\n", pf_name(key->zsbuf_format));
+         debug_printf("depth.func = %s\n", debug_dump_func(key->depth.func, TRUE));
+         debug_printf("depth.writemask = %u\n", key->depth.writemask);
+      }
+      if(key->alpha.enabled) {
+         debug_printf("alpha.func = %s\n", debug_dump_func(key->alpha.func, TRUE));
+         debug_printf("alpha.ref_value = %f\n", key->alpha.ref_value);
+      }
+      if(key->blend.logicop_enable) {
+         debug_printf("blend.logicop_func = %u\n", key->blend.logicop_func);
+      }
+      else if(key->blend.blend_enable) {
+         debug_printf("blend.rgb_func = %s\n",   debug_dump_blend_func  (key->blend.rgb_func, TRUE));
+         debug_printf("rgb_src_factor = %s\n",   debug_dump_blend_factor(key->blend.rgb_src_factor, TRUE));
+         debug_printf("rgb_dst_factor = %s\n",   debug_dump_blend_factor(key->blend.rgb_dst_factor, TRUE));
+         debug_printf("alpha_func = %s\n",       debug_dump_blend_func  (key->blend.alpha_func, TRUE));
+         debug_printf("alpha_src_factor = %s\n", debug_dump_blend_factor(key->blend.alpha_src_factor, TRUE));
+         debug_printf("alpha_dst_factor = %s\n", debug_dump_blend_factor(key->blend.alpha_dst_factor, TRUE));
+      }
+      debug_printf("blend.colormask = 0x%x\n", key->blend.colormask);
+      for(i = 0; i < PIPE_MAX_SAMPLERS; ++i) {
+         if(key->sampler[i].format) {
+            debug_printf("sampler[%u] = \n", i);
+            debug_printf("  .format = %s\n",
+                         pf_name(key->sampler[i].format));
+            debug_printf("  .target = %s\n",
+                         debug_dump_tex_target(key->sampler[i].target, TRUE));
+            debug_printf("  .pot = %u %u %u\n",
+                         key->sampler[i].pot_width,
+                         key->sampler[i].pot_height,
+                         key->sampler[i].pot_depth);
+            debug_printf("  .wrap = %s %s %s\n",
+                         debug_dump_tex_wrap(key->sampler[i].wrap_s, TRUE),
+                         debug_dump_tex_wrap(key->sampler[i].wrap_t, TRUE),
+                         debug_dump_tex_wrap(key->sampler[i].wrap_r, TRUE));
+            debug_printf("  .min_img_filter = %s\n",
+                         debug_dump_tex_filter(key->sampler[i].min_img_filter, TRUE));
+            debug_printf("  .min_mip_filter = %s\n",
+                         debug_dump_tex_mipfilter(key->sampler[i].min_mip_filter, TRUE));
+            debug_printf("  .mag_img_filter = %s\n",
+                         debug_dump_tex_filter(key->sampler[i].mag_img_filter, TRUE));
+            if(key->sampler[i].compare_mode != PIPE_TEX_COMPARE_NONE)
+               debug_printf("  .compare_func = %s\n", debug_dump_func(key->sampler[i].compare_func, TRUE));
+            debug_printf("  .normalized_coords = %u\n", key->sampler[i].normalized_coords);
+            debug_printf("  .prefilter = %u\n", key->sampler[i].prefilter);
+         }
+      }
+   }
+
+   variant = CALLOC_STRUCT(lp_fragment_shader_variant);
+   if(!variant)
+      return NULL;
+
+   variant->shader = shader;
+   memcpy(&variant->key, key, sizeof *key);
+
+   generate_fragment(lp, shader, variant);
 
    return variant;
 }
@@ -631,7 +917,12 @@ llvmpipe_bind_fs_state(struct pipe_context *pipe, void *fs)
 {
    struct llvmpipe_context *llvmpipe = llvmpipe_context(pipe);
 
-   llvmpipe->fs = (struct lp_fragment_shader *) fs;
+   if (llvmpipe->fs == fs)
+      return;
+
+   draw_flush(llvmpipe->draw);
+
+   llvmpipe->fs = fs;
 
    llvmpipe->dirty |= LP_NEW_FS;
 }
@@ -646,6 +937,7 @@ llvmpipe_delete_fs_state(struct pipe_context *pipe, void *fs)
    struct lp_fragment_shader_variant *variant;
 
    assert(fs != llvmpipe->fs);
+   (void) llvmpipe;
 
    variant = shader->variants;
    while(variant) {
@@ -671,16 +963,28 @@ llvmpipe_delete_fs_state(struct pipe_context *pipe, void *fs)
 void
 llvmpipe_set_constant_buffer(struct pipe_context *pipe,
                              uint shader, uint index,
-                             const struct pipe_constant_buffer *buf)
+                             const struct pipe_constant_buffer *constants)
 {
    struct llvmpipe_context *llvmpipe = llvmpipe_context(pipe);
+   struct pipe_buffer *buffer = constants ? constants->buffer : NULL;
+   unsigned size = buffer ? buffer->size : 0;
+   const void *data = buffer ? llvmpipe_buffer(buffer)->data : NULL;
 
    assert(shader < PIPE_SHADER_TYPES);
    assert(index == 0);
 
+   if(llvmpipe->constants[shader].buffer == buffer)
+      return;
+
+   draw_flush(llvmpipe->draw);
+
    /* note: reference counting */
-   pipe_buffer_reference(&llvmpipe->constants[shader].buffer,
-                        buf ? buf->buffer : NULL);
+   pipe_buffer_reference(&llvmpipe->constants[shader].buffer, buffer);
+
+   if(shader == PIPE_SHADER_VERTEX) {
+      draw_set_mapped_constant_buffer(llvmpipe->draw, PIPE_SHADER_VERTEX,
+                                      data, size);
+   }
 
    llvmpipe->dirty |= LP_NEW_CONSTANTS;
 }
@@ -713,21 +1017,30 @@ make_variant_key(struct llvmpipe_context *lp,
       key->alpha.func = lp->depth_stencil->alpha.func;
    /* alpha.ref_value is passed in jit_context */
 
-   if(lp->framebuffer.cbufs[0]) {
-      const struct util_format_description *format_desc;
-      unsigned chan;
+   key->flatshade = lp->rasterizer->flatshade;
+   key->scissor = lp->rasterizer->scissor;
 
+   if (lp->framebuffer.nr_cbufs) {
       memcpy(&key->blend, lp->blend, sizeof key->blend);
+   }
+
+   key->nr_cbufs = lp->framebuffer.nr_cbufs;
+   for (i = 0; i < lp->framebuffer.nr_cbufs; i++) {
+      const struct util_format_description *format_desc;
+      unsigned chan;
 
-      format_desc = util_format_description(lp->framebuffer.cbufs[0]->format);
+      format_desc = util_format_description(lp->framebuffer.cbufs[i]->format);
       assert(format_desc->layout == UTIL_FORMAT_COLORSPACE_RGB ||
              format_desc->layout == UTIL_FORMAT_COLORSPACE_SRGB);
 
-      /* mask out color channels not present in the color buffer */
+      /* mask out color channels not present in the color buffer.
+       * Should be simple to incorporate per-cbuf writemasks:
+       */
       for(chan = 0; chan < 4; ++chan) {
          enum util_format_swizzle swizzle = format_desc->swizzle[chan];
-         if(swizzle > 4)
-            key->blend.colormask &= ~(1 << chan);
+
+         if(swizzle <= UTIL_FORMAT_SWIZZLE_W)
+            key->cbuf_blend[i].colormask |= (1 << chan);
       }
    }
 
@@ -737,12 +1050,17 @@ make_variant_key(struct llvmpipe_context *lp,
 }
 
 
+/**
+ * Update fragment state.  This is called just prior to drawing
+ * something when some fragment-related state has changed.
+ */
 void 
 llvmpipe_update_fs(struct llvmpipe_context *lp)
 {
    struct lp_fragment_shader *shader = lp->fs;
    struct lp_fragment_shader_variant_key key;
    struct lp_fragment_shader_variant *variant;
+   boolean opaque;
 
    make_variant_key(lp, shader, &key);
 
@@ -755,7 +1073,22 @@ llvmpipe_update_fs(struct llvmpipe_context *lp)
    }
 
    if(!variant)
-      variant = generate_fragment(lp, shader, &key);
+      variant = generate_variant(lp, shader, &key);
 
    shader->current = variant;
+
+   /* TODO: put this in the variant */
+   /* TODO: most of these can be relaxed, in particular the colormask */
+   opaque = !key.blend.logicop_enable &&
+            !key.blend.blend_enable &&
+            key.blend.colormask == 0xf &&
+            !key.alpha.enabled &&
+            !key.depth.enabled &&
+            !key.scissor &&
+            !shader->info.uses_kill
+            ? TRUE : FALSE;
+
+   lp_setup_set_fs_function(lp->setup, 
+                            shader->current->jit_function,
+                            opaque);
 }