Grammar and spelling fixes

[mesa.git] / src / mesa / swrast / s_depth.c

diff --git a/src/mesa/swrast/s_depth.c b/src/mesa/swrast/s_depth.c
index 0b6bb7e3ec96be589cf80d751421461ccbb0e02a..ed637cac1245a8668dfdcf863e3a37ce045291de 100644 (file)
--- a/src/mesa/swrast/s_depth.c
+++ b/src/mesa/swrast/s_depth.c
@@ -259,7 +259,7 @@ depth_test_span16( GLcontext *ctx, GLuint n,
         }
         break;
       case GL_NEVER:
-         _mesa_bzero(mask, n * sizeof(GLubyte));
+         memset(mask, 0, n * sizeof(GLubyte));
         break;
       default:
          _mesa_problem(ctx, "Bad depth func in depth_test_span16");
@@ -488,7 +488,7 @@ depth_test_span32( GLcontext *ctx, GLuint n,
         }
         break;
       case GL_NEVER:
-         _mesa_bzero(mask, n * sizeof(GLubyte));
+         memset(mask, 0, n * sizeof(GLubyte));
         break;
       default:
          _mesa_problem(ctx, "Bad depth func in depth_test_span32");
@@ -497,17 +497,24 @@ depth_test_span32( GLcontext *ctx, GLuint n,
    return passed;
 }
 
-/* Apply ARB_depth_clamp to span of fragments. */
+
+
+/**
+ * Clamp fragment Z values to the depth near/far range (glDepthRange()).
+ * This is used when GL_ARB_depth_clamp/GL_DEPTH_CLAMP is turned on.
+ * In that case, vertexes are not clipped against the near/far planes
+ * so rasterization will produce fragment Z values outside the usual
+ * [0,1] range.
+ */
 void
 _swrast_depth_clamp_span( GLcontext *ctx, SWspan *span )
 {
    struct gl_framebuffer *fb = ctx->DrawBuffer;
-   struct gl_renderbuffer *rb = fb->_DepthBuffer;
    const GLuint count = span->end;
-   GLuint *zValues = span->array->z;
-   GLuint min, max;
+   GLint *zValues = (GLint *) span->array->z; /* sign change */
+   GLint min, max;
    GLfloat min_f, max_f;
-   int i;
+   GLuint i;
 
    if (ctx->Viewport.Near < ctx->Viewport.Far) {
       min_f = ctx->Viewport.Near;
@@ -517,15 +524,21 @@ _swrast_depth_clamp_span( GLcontext *ctx, SWspan *span )
       max_f = ctx->Viewport.Near;
    }
 
-   if (rb->DataType == GL_UNSIGNED_SHORT) {
-      CLAMPED_FLOAT_TO_USHORT(min, min_f);
-      CLAMPED_FLOAT_TO_USHORT(max, max_f);
-   } else {
-      assert(rb->DataType == GL_UNSIGNED_INT);
-      min = FLOAT_TO_UINT(min_f);
-      max = FLOAT_TO_UINT(max_f);
-   }
-
+   /* Convert floating point values in [0,1] to device Z coordinates in
+    * [0, DepthMax].
+    * ex: If the Z buffer has 24 bits, DepthMax = 0xffffff.
+    * 
+    * XXX this all falls apart if we have 31 or more bits of Z because
+    * the triangle rasterization code produces unsigned Z values.  Negative
+    * vertex Z values come out as large fragment Z uints.
+    */
+   min = (GLint) (min_f * fb->_DepthMaxF);
+   max = (GLint) (max_f * fb->_DepthMaxF);
+   if (max < 0)
+      max = 0x7fffffff; /* catch over flow for 30-bit z */
+
+   /* Note that we do the comparisons here using signed integers.
+    */
    for (i = 0; i < count; i++) {
       if (zValues[i] < min)
         zValues[i] = min;
@@ -831,7 +844,7 @@ direct_depth_test_pixels16(GLcontext *ctx, GLushort *zStart, GLuint stride,
         break;
       case GL_NEVER:
         /* depth test never passes */
-         _mesa_bzero(mask, n * sizeof(GLubyte));
+         memset(mask, 0, n * sizeof(GLubyte));
         break;
       default:
          _mesa_problem(ctx, "Bad depth func in direct_depth_test_pixels");
@@ -1077,7 +1090,7 @@ direct_depth_test_pixels32(GLcontext *ctx, GLuint *zStart, GLuint stride,
         break;
       case GL_NEVER:
         /* depth test never passes */
-         _mesa_bzero(mask, n * sizeof(GLubyte));
+         memset(mask, 0, n * sizeof(GLubyte));
         break;
       default:
          _mesa_problem(ctx, "Bad depth func in direct_depth_test_pixels");
@@ -1247,7 +1260,7 @@ _swrast_read_depth_span_float( GLcontext *ctx, struct gl_renderbuffer *rb,
 
    if (!rb) {
       /* really only doing this to prevent FP exceptions later */
-      _mesa_bzero(depth, n * sizeof(GLfloat));
+      memset(depth, 0, n * sizeof(GLfloat));
       return;
    }
 
@@ -1256,7 +1269,7 @@ _swrast_read_depth_span_float( GLcontext *ctx, struct gl_renderbuffer *rb,
    if (y < 0 || y >= (GLint) rb->Height ||
        x + n <= 0 || x >= (GLint) rb->Width) {
       /* span is completely outside framebuffer */
-      _mesa_bzero(depth, n * sizeof(GLfloat));
+      memset(depth, 0, n * sizeof(GLfloat));
       return;
    }
 
@@ -1313,7 +1326,7 @@ _swrast_read_depth_span_uint( GLcontext *ctx, struct gl_renderbuffer *rb,
 
    if (!rb) {
       /* really only doing this to prevent FP exceptions later */
-      _mesa_bzero(depth, n * sizeof(GLuint));
+      memset(depth, 0, n * sizeof(GLuint));
       return;
    }
 
@@ -1324,7 +1337,7 @@ _swrast_read_depth_span_uint( GLcontext *ctx, struct gl_renderbuffer *rb,
    if (y < 0 || y >= (GLint) rb->Height ||
        x + n <= 0 || x >= (GLint) rb->Width) {
       /* span is completely outside framebuffer */
-      _mesa_bzero(depth, n * sizeof(GLfloat));
+      memset(depth, 0, n * sizeof(GLfloat));
       return;
    }
 
@@ -1425,7 +1438,7 @@ _swrast_clear_depth_buffer( GLcontext *ctx, struct gl_renderbuffer *rb )
             /* optimized case */
             GLushort *dst = (GLushort *) rb->GetPointer(ctx, rb, x, y);
             GLuint len = width * height * sizeof(GLushort);
-            _mesa_memset(dst, (clearValue & 0xff), len);
+            memset(dst, (clearValue & 0xff), len);
          }
          else {
             /* general case */