1 files changed, 81 insertions, 0 deletions
diff --git a/src/mesa/main/texfetch.c b/src/mesa/main/texfetch.c
index 62a8b534099..3428f705be8 100644
--- a/src/mesa/main/texfetch.c
+++ b/src/mesa/main/texfetch.c
@@ -565,3 +565,84 @@ _mesa_get_texel_store_func(gl_format format)
    }
    return NULL;
 }
+
+
+
+/**
+ * Adaptor for fetching a GLchan texel from a float-valued texture.
+ */
+static void
+fetch_texel_float_to_chan(const struct gl_texture_image *texImage,
+                          GLint i, GLint j, GLint k, GLchan *texelOut)
+{
+   GLfloat temp[4];
+   GLenum baseFormat = _mesa_get_format_base_format(texImage->TexFormat);
+
+   ASSERT(texImage->FetchTexelf);
+   texImage->FetchTexelf(texImage, i, j, k, temp);
+   if (baseFormat == GL_DEPTH_COMPONENT ||
+       baseFormat == GL_DEPTH_STENCIL_EXT) {
+      /* just one channel */
+      UNCLAMPED_FLOAT_TO_CHAN(texelOut[0], temp[0]);
+   }
+   else {
+      /* four channels */
+      UNCLAMPED_FLOAT_TO_CHAN(texelOut[0], temp[0]);
+      UNCLAMPED_FLOAT_TO_CHAN(texelOut[1], temp[1]);
+      UNCLAMPED_FLOAT_TO_CHAN(texelOut[2], temp[2]);
+      UNCLAMPED_FLOAT_TO_CHAN(texelOut[3], temp[3]);
+   }
+}
+
+
+/**
+ * Adaptor for fetching a float texel from a GLchan-valued texture.
+ */
+static void
+fetch_texel_chan_to_float(const struct gl_texture_image *texImage,
+                          GLint i, GLint j, GLint k, GLfloat *texelOut)
+{
+   GLchan temp[4];
+   GLenum baseFormat = _mesa_get_format_base_format(texImage->TexFormat);
+
+   ASSERT(texImage->FetchTexelc);
+   texImage->FetchTexelc(texImage, i, j, k, temp);
+   if (baseFormat == GL_DEPTH_COMPONENT ||
+       baseFormat == GL_DEPTH_STENCIL_EXT) {
+      /* just one channel */
+      texelOut[0] = CHAN_TO_FLOAT(temp[0]);
+   }
+   else {
+      /* four channels */
+      texelOut[0] = CHAN_TO_FLOAT(temp[0]);
+      texelOut[1] = CHAN_TO_FLOAT(temp[1]);
+      texelOut[2] = CHAN_TO_FLOAT(temp[2]);
+      texelOut[3] = CHAN_TO_FLOAT(temp[3]);
+   }
+}
+
+
+/**
+ * Initialize the texture image's FetchTexelc and FetchTexelf methods.
+ */
+void
+_mesa_set_fetch_functions(struct gl_texture_image *texImage, GLuint dims)
+{
+   ASSERT(dims == 1 || dims == 2 || dims == 3);
+   ASSERT(texImage->TexFormat);
+
+   texImage->FetchTexelf =
+      _mesa_get_texel_fetch_func(texImage->TexFormat, dims);
+
+   /* now check if we need to use a float/chan adaptor */
+   if (!texImage->FetchTexelc) {
+      texImage->FetchTexelc = fetch_texel_float_to_chan;
+   }
+   else if (!texImage->FetchTexelf) {
+      texImage->FetchTexelf = fetch_texel_chan_to_float;
+   }
+
+
+   ASSERT(texImage->FetchTexelc);
+   ASSERT(texImage->FetchTexelf);
+}