+/**
+ * Fetch texel from texture. Use partial derivatives when possible.
+ */
+static INLINE void
+fetch_texel(GLcontext *ctx,
+ const struct gl_program_machine *machine,
+ const struct prog_instruction *inst,
+ const GLfloat texcoord[4], GLfloat lodBias,
+ GLfloat color[4])
+{
+ const GLuint unit = machine->Samplers[inst->TexSrcUnit];
+
+ /* Note: we only have the right derivatives for fragment input attribs.
+ */
+ if (machine->NumDeriv > 0 &&
+ inst->SrcReg[0].File == PROGRAM_INPUT &&
+ inst->SrcReg[0].Index == FRAG_ATTRIB_TEX0 + inst->TexSrcUnit) {
+ /* simple texture fetch for which we should have derivatives */
+ GLuint attr = inst->SrcReg[0].Index;
+ machine->FetchTexelDeriv(ctx, texcoord,
+ machine->DerivX[attr],
+ machine->DerivY[attr],
+ lodBias, unit, color);
+ }
+ else {
+ machine->FetchTexelLod(ctx, texcoord, lodBias, unit, color);
+ }
+}
+
+