Kenneth Graunke <kenn...@whitecape.org> writes: > Intel hardware doesn't natively support textureGrad with shadow > comparisons. So we need to generate code to handle it somehow. > > Based on the equations of page 205 of the OpenGL 3.0 specification, > it's possible to compute the LOD value that would be selected given the > gradient values. Then, we can simply convert the TXD to a TXL. > > Currently, this passes 38/46 of oglconform's shadow-grad subtests, > and selects the wrong level for the other 6 (but doesn't crash). > > While we should investigate the remaining failures, this new method at > least works better than the old one. Texturing with explicit gradients, > shadow sampling, and either projection or texel offsets is pretty > obscure anyway. > > Signed-off-by: Kenneth Graunke <kenn...@whitecape.org> > --- > src/mesa/drivers/dri/i965/Makefile.sources | 1 + > src/mesa/drivers/dri/i965/brw_context.h | 1 + > .../dri/i965/brw_lower_texture_gradients.cpp | 153 > ++++++++++++++++++++ > src/mesa/drivers/dri/i965/brw_shader.cpp | 1 + > 4 files changed, 156 insertions(+) > create mode 100644 src/mesa/drivers/dri/i965/brw_lower_texture_gradients.cpp > > diff --git a/src/mesa/drivers/dri/i965/Makefile.sources > b/src/mesa/drivers/dri/i965/Makefile.sources > index 82143ac..334bfd9 100644 > --- a/src/mesa/drivers/dri/i965/Makefile.sources > +++ b/src/mesa/drivers/dri/i965/Makefile.sources > @@ -125,6 +125,7 @@ i965_CXX_FILES = \ > brw_fs_reg_allocate.cpp \ > brw_fs_schedule_instructions.cpp \ > brw_fs_vector_splitting.cpp \ > + brw_lower_texture_gradients.cpp \ > brw_shader.cpp \ > brw_vec4.cpp \ > brw_vec4_emit.cpp \ > diff --git a/src/mesa/drivers/dri/i965/brw_context.h > b/src/mesa/drivers/dri/i965/brw_context.h > index c1f2314..b4868fe 100644 > --- a/src/mesa/drivers/dri/i965/brw_context.h > +++ b/src/mesa/drivers/dri/i965/brw_context.h > @@ -1276,6 +1276,7 @@ brw_program_reloc(struct brw_context *brw, uint32_t > state_offset, > } > > bool brw_do_cubemap_normalize(struct exec_list *instructions); > +bool brw_lower_texture_gradients(struct exec_list *instructions); > > #ifdef __cplusplus > } > diff --git a/src/mesa/drivers/dri/i965/brw_lower_texture_gradients.cpp > b/src/mesa/drivers/dri/i965/brw_lower_texture_gradients.cpp > new file mode 100644 > index 0000000..2d4f2ab > --- /dev/null > +++ b/src/mesa/drivers/dri/i965/brw_lower_texture_gradients.cpp
> + /* Calculate rho from equation 3.20 of the GL 3.0 specification. */
> + ir_rvalue *rho;
> + if (dPdx->type->is_scalar()) {
> + rho = expr(ir_binop_max, dPdx, dPdy);
> + } else {
> + rho = expr(ir_binop_max, expr(ir_unop_sqrt, dot(dPdx, dPdx)),
> + expr(ir_unop_sqrt, dot(dPdy, dPdy)));
> + }
Does the is_scalar() case need an abs() on the two args? I was thinking
"huh, it would be cool if we recognized how to make the second
expression better automatically", and realized that it doesn't quite
reduce to the is_scalar() case.
Other than that, this series is
Reviewed-by: Eric Anholt <e...@anholt.net>
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