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 /**
  19  * Derived from gl_renderbuffer class
  20  */
  21 struct texture_renderbuffer
  22 {
  23    struct gl_renderbuffer Base;   /**< Base class object */
  24    struct swrast_texture_image *TexImage;
  25    StoreTexelFunc Store;
  26    FetchTexelFunc Fetch;
  27    GLint Yoffset;                 /**< Layer for 1D array textures. */
  28    GLint Zoffset;                 /**< Layer for 2D array textures, or slice
  29                                    * for 3D textures
  30                                    */
  31 };
  32
  33
  34 /** cast wrapper */
  35 static inline struct texture_renderbuffer *
  36 texture_renderbuffer(struct gl_renderbuffer *rb)
  37 {
  38    return (struct texture_renderbuffer *) rb;
  39 }
  40
  41
  42
  43
  44 static void
  45 store_nop(struct swrast_texture_image *texImage,
  46           GLint col, GLint row, GLint img,
  47           const void *texel)
  48 {
  49 }
  50
  51
  52 static void
  53 delete_texture_wrapper(struct gl_renderbuffer *rb)
  54 {
  55    ASSERT(rb->RefCount == 0);
  56    free(rb);
  57 }
  58
  59
  60 /**
  61  * This function creates a renderbuffer object which wraps a texture image.
  62  * The new renderbuffer is plugged into the given attachment point.
  63  * This allows rendering into the texture as if it were a renderbuffer.
  64  */
  65 static void
  66 wrap_texture(struct gl_context *ctx, struct gl_renderbuffer_attachment *att)
  67 {
  68    struct texture_renderbuffer *trb;
  69    const GLuint name = 0;
  70
  71    ASSERT(att->Type == GL_TEXTURE);
  72    ASSERT(att->Renderbuffer == NULL);
  73
  74    trb = CALLOC_STRUCT(texture_renderbuffer);
  75    if (!trb) {
  76       _mesa_error(ctx, GL_OUT_OF_MEMORY, "wrap_texture");
  77       return;
  78    }
  79
  80    /* init base gl_renderbuffer fields */
  81    _mesa_init_renderbuffer(&trb->Base, name);
  82    /* plug in our texture_renderbuffer-specific functions */
  83    trb->Base.Delete = delete_texture_wrapper;
  84    trb->Base.AllocStorage = NULL; /* illegal! */
  85
  86    /* update attachment point */
  87    _mesa_reference_renderbuffer(&att->Renderbuffer, &(trb->Base));
  88 }
  89
  90 /**
  91  * Update the renderbuffer wrapper for rendering to a texture.
  92  * For example, update the width, height of the RB based on the texture size,
  93  * update the internal format info, etc.
  94  */
  95 static void
  96 update_wrapper(struct gl_context *ctx, struct gl_renderbuffer_attachment *att)
  97 {
  98    struct texture_renderbuffer *trb
  99       = (struct texture_renderbuffer *) att->Renderbuffer;
 100
 101    (void) ctx;
 102    ASSERT(trb);
 103
 104    trb->TexImage = swrast_texture_image(_mesa_get_attachment_teximage(att));
 105    ASSERT(trb->TexImage);
 106
 107    trb->Store = _mesa_get_texel_store_func(trb->TexImage->Base.TexFormat);
 108    if (!trb->Store) {
 109       /* we'll never draw into some textures (compressed formats) */
 110       trb->Store = store_nop;
 111    }
 112
 113    if (!trb->TexImage->FetchTexel) {
 114       _mesa_update_fetch_functions(trb->TexImage->Base.TexObject);
 115    }
 116    trb->Fetch = trb->TexImage->FetchTexel;
 117    assert(trb->Fetch);
 118
 119    if (att->Texture->Target == GL_TEXTURE_1D_ARRAY_EXT) {
 120       trb->Yoffset = att->Zoffset;
 121       trb->Zoffset = 0;
 122    }
 123    else {
 124       trb->Yoffset = 0;
 125       trb->Zoffset = att->Zoffset;
 126    }
 127
 128    trb->Base.Width = trb->TexImage->Base.Width;
 129    trb->Base.Height = trb->TexImage->Base.Height;
 130    trb->Base.InternalFormat = trb->TexImage->Base.InternalFormat;
 131    trb->Base.Format = trb->TexImage->Base.TexFormat;
 132
 133    /* Set the gl_renderbuffer::Data field so that mapping the buffer
 134     * in renderbuffer.c succeeds.
 135     */
 136    if (att->Texture->Target == GL_TEXTURE_3D ||
 137        att->Texture->Target == GL_TEXTURE_2D_ARRAY_EXT) {
 138       trb->Base.Data = trb->TexImage->Buffer +
 139          trb->TexImage->ImageOffsets[trb->Zoffset] *
 140          _mesa_get_format_bytes(trb->TexImage->Base.TexFormat);
 141    }
 142    else {
 143       trb->Base.Data = trb->TexImage->Buffer;
 144    }
 145
 146    /* XXX may need more special cases here */
 147    switch (trb->TexImage->Base.TexFormat) {
 148    case MESA_FORMAT_Z24_S8:
 149       trb->Base._BaseFormat = GL_DEPTH_STENCIL;
 150       break;
 151    case MESA_FORMAT_S8_Z24:
 152       trb->Base._BaseFormat = GL_DEPTH_STENCIL;
 153       break;
 154    case MESA_FORMAT_Z24_X8:
 155       trb->Base._BaseFormat = GL_DEPTH_COMPONENT;
 156       break;
 157    case MESA_FORMAT_X8_Z24:
 158       trb->Base._BaseFormat = GL_DEPTH_COMPONENT;
 159       break;
 160    case MESA_FORMAT_Z16:
 161       trb->Base._BaseFormat = GL_DEPTH_COMPONENT;
 162       break;
 163    case MESA_FORMAT_Z32:
 164       trb->Base._BaseFormat = GL_DEPTH_COMPONENT;
 165       break;
 166    /* SRGB formats pre EXT_framebuffer_sRGB don't do sRGB translations on FBO readback */
 167    case MESA_FORMAT_SRGB8:
 168       trb->Fetch = _mesa_get_texel_fetch_func(MESA_FORMAT_RGB888, _mesa_get_texture_dimensions(att->Texture->Target));
 169       trb->Base._BaseFormat = GL_RGBA;
 170       break;
 171    case MESA_FORMAT_SRGBA8:
 172       trb->Fetch = _mesa_get_texel_fetch_func(MESA_FORMAT_RGBA8888, _mesa_get_texture_dimensions(att->Texture->Target));
 173       trb->Base._BaseFormat = GL_RGBA;
 174       break;
 175    case MESA_FORMAT_SARGB8:
 176       trb->Fetch = _mesa_get_texel_fetch_func(MESA_FORMAT_ARGB8888, _mesa_get_texture_dimensions(att->Texture->Target));
 177       trb->Base._BaseFormat = GL_RGBA;
 178       break;
 179    default:
 180       trb->Base._BaseFormat = GL_RGBA;
 181    }
 182 }
 183
 184
 185
 186 /**
 187  * Called when rendering to a texture image begins, or when changing
 188  * the dest mipmap level, cube face, etc.
 189  * This is a fallback routine for software render-to-texture.
 190  *
 191  * Called via the glRenderbufferTexture1D/2D/3D() functions
 192  * and elsewhere (such as glTexImage2D).
 193  *
 194  * The image we're rendering into is
 195  * att->Texture->Image[att->CubeMapFace][att->TextureLevel];
 196  * It'll never be NULL.
 197  *
 198  * \param fb  the framebuffer object the texture is being bound to
 199  * \param att  the fb attachment point of the texture
 200  *
 201  * \sa _mesa_framebuffer_renderbuffer
 202  */
 203 void
 204 _swrast_render_texture(struct gl_context *ctx,
 205                        struct gl_framebuffer *fb,
 206                        struct gl_renderbuffer_attachment *att)
 207 {
 208    (void) fb;
 209
 210    if (!att->Renderbuffer) {
 211       wrap_texture(ctx, att);
 212    }
 213    update_wrapper(ctx, att);
 214 }
 215
 216
 217 void
 218 _swrast_finish_render_texture(struct gl_context *ctx,
 219                               struct gl_renderbuffer_attachment *att)
 220 {
 221    /* do nothing */
 222    /* The renderbuffer texture wrapper will get deleted by the
 223     * normal mechanism for deleting renderbuffers.
 224     */
 225    (void) ctx;
 226    (void) att;
 227 }