src/mesa/swrast/s_texrender.c

   1
   2 #include "main/context.h"
   3 #include "main/colormac.h"
   4 #include "main/fbobject.h"
   5 #include "main/macros.h"
   6 #include "main/teximage.h"
   7 #include "main/renderbuffer.h"
   8 #include "swrast/swrast.h"
   9 #include "swrast/s_context.h"
  10 #include "swrast/s_texfetch.h"
  11
  12
  13 /*
  14  * Render-to-texture code for GL_EXT_framebuffer_object
  15  */
  16
  17
  18 static void
  19 delete_texture_wrapper(struct gl_context *ctx, struct gl_renderbuffer *rb)
  20 {
  21    ASSERT(rb->RefCount == 0);
  22    free(rb);
  23 }
  24
  25
  26 /**
  27  * This function creates a renderbuffer object which wraps a texture image.
  28  * The new renderbuffer is plugged into the given attachment point.
  29  * This allows rendering into the texture as if it were a renderbuffer.
  30  */
  31 static void
  32 wrap_texture(struct gl_context *ctx, struct gl_renderbuffer_attachment *att)
  33 {
  34    struct gl_renderbuffer *rb;
  35    const GLuint name = 0;
  36
  37    ASSERT(att->Type == GL_TEXTURE);
  38    ASSERT(att->Renderbuffer == NULL);
  39
  40    rb = ctx->Driver.NewRenderbuffer(ctx, name);
  41    if (!rb) {
  42       _mesa_error(ctx, GL_OUT_OF_MEMORY, "wrap_texture");
  43       return;
  44    }
  45
  46    /* init base gl_renderbuffer fields */
  47    _mesa_init_renderbuffer(rb, name);
  48    /* plug in our texture_renderbuffer-specific functions */
  49    rb->Delete = delete_texture_wrapper;
  50    rb->AllocStorage = NULL; /* illegal! */
  51
  52    /* update attachment point */
  53    _mesa_reference_renderbuffer(&att->Renderbuffer, rb);
  54 }
  55
  56 /**
  57  * Update the renderbuffer wrapper for rendering to a texture.
  58  * For example, update the width, height of the RB based on the texture size,
  59  * update the internal format info, etc.
  60  */
  61 static void
  62 update_wrapper(struct gl_context *ctx, struct gl_renderbuffer_attachment *att)
  63 {
  64    struct gl_renderbuffer *rb = att->Renderbuffer;
  65    struct swrast_renderbuffer *srb = swrast_renderbuffer(rb);
  66    struct swrast_texture_image *swImage;
  67    gl_format format;
  68    GLuint zOffset;
  69
  70    (void) ctx;
  71
  72    swImage = swrast_texture_image(_mesa_get_attachment_teximage(att));
  73    assert(swImage);
  74
  75    format = swImage->Base.TexFormat;
  76
  77    if (att->Texture->Target == GL_TEXTURE_1D_ARRAY_EXT) {
  78       zOffset = 0;
  79    }
  80    else {
  81       zOffset = att->Zoffset;
  82    }
  83
  84    rb->Width = swImage->Base.Width;
  85    rb->Height = swImage->Base.Height;
  86    rb->InternalFormat = swImage->Base.InternalFormat;
  87    rb->_BaseFormat = _mesa_get_format_base_format(format);
  88
  89    /* Want to store linear values, not sRGB */
  90    rb->Format = _mesa_get_srgb_format_linear(format);
  91
  92    /* Set the gl_renderbuffer::Buffer field so that mapping the buffer
  93     * succeeds.
  94      */
  95    if (att->Texture->Target == GL_TEXTURE_3D ||
  96        att->Texture->Target == GL_TEXTURE_2D_ARRAY_EXT) {
  97       srb->Buffer = swImage->Buffer +
  98          swImage->ImageOffsets[zOffset] * _mesa_get_format_bytes(format);
  99    }
 100    else {
 101       srb->Buffer = swImage->Buffer;
 102    }
 103 }
 104
 105
 106
 107 /**
 108  * Called when rendering to a texture image begins, or when changing
 109  * the dest mipmap level, cube face, etc.
 110  * This is a fallback routine for software render-to-texture.
 111  *
 112  * Called via the glRenderbufferTexture1D/2D/3D() functions
 113  * and elsewhere (such as glTexImage2D).
 114  *
 115  * The image we're rendering into is
 116  * att->Texture->Image[att->CubeMapFace][att->TextureLevel];
 117  * It'll never be NULL.
 118  *
 119  * \param fb  the framebuffer object the texture is being bound to
 120  * \param att  the fb attachment point of the texture
 121  *
 122  * \sa _mesa_framebuffer_renderbuffer
 123  */
 124 void
 125 _swrast_render_texture(struct gl_context *ctx,
 126                        struct gl_framebuffer *fb,
 127                        struct gl_renderbuffer_attachment *att)
 128 {
 129    (void) fb;
 130
 131    if (!att->Renderbuffer) {
 132       wrap_texture(ctx, att);
 133    }
 134    update_wrapper(ctx, att);
 135 }
 136
 137
 138 void
 139 _swrast_finish_render_texture(struct gl_context *ctx,
 140                               struct gl_renderbuffer_attachment *att)
 141 {
 142    /* do nothing */
 143    /* The renderbuffer texture wrapper will get deleted by the
 144     * normal mechanism for deleting renderbuffers.
 145     */
 146    (void) ctx;
 147    (void) att;
 148 }