v2: Fix the x_scale in the shader. Remove the doubts in the commit message. ---
After some helpful explanation from Anuj and reading the code a bit more, I think I understand this a bit better and I no longer think there is an issue with the sample map array having out-of-bounds indices. The texture coordinates are effectively multiplied by ‘scale’, converted to integers and then divided by scale again. That means that fract(coord) can effectively only be a multiple of 1.0/scale. In the 8x MSAA case, 1.0/scale is vec2(0.5f, 0.25f) which means the maximum array index is int(0.5*2.0 + 0.75*8.0) == 7. In this v2 of the patch I've fixed scale.x in the shader. Now for the 16x MSAA case 1.0/scale is vec2(0.25f,0.25f). I've left the formula for the array index the same as v1 so the maximum index is now int(0.75*4.0 + 0.75*16) == 15 which makes sense. src/mesa/drivers/common/meta.h | 2 ++ src/mesa/drivers/common/meta_blit.c | 29 ++++++++++++++-------- src/mesa/drivers/dri/i965/gen6_multisample_state.c | 14 +++++++++++ src/mesa/main/mtypes.h | 15 ++++++++++- 4 files changed, 49 insertions(+), 11 deletions(-) diff --git a/src/mesa/drivers/common/meta.h b/src/mesa/drivers/common/meta.h index fe43915..e42ddc8 100644 --- a/src/mesa/drivers/common/meta.h +++ b/src/mesa/drivers/common/meta.h @@ -285,9 +285,11 @@ enum blit_msaa_shader { BLIT_2X_MSAA_SHADER_2D_MULTISAMPLE_SCALED_RESOLVE, BLIT_4X_MSAA_SHADER_2D_MULTISAMPLE_SCALED_RESOLVE, BLIT_8X_MSAA_SHADER_2D_MULTISAMPLE_SCALED_RESOLVE, + BLIT_16X_MSAA_SHADER_2D_MULTISAMPLE_SCALED_RESOLVE, BLIT_2X_MSAA_SHADER_2D_MULTISAMPLE_ARRAY_SCALED_RESOLVE, BLIT_4X_MSAA_SHADER_2D_MULTISAMPLE_ARRAY_SCALED_RESOLVE, BLIT_8X_MSAA_SHADER_2D_MULTISAMPLE_ARRAY_SCALED_RESOLVE, + BLIT_16X_MSAA_SHADER_2D_MULTISAMPLE_ARRAY_SCALED_RESOLVE, BLIT_MSAA_SHADER_COUNT, }; diff --git a/src/mesa/drivers/common/meta_blit.c b/src/mesa/drivers/common/meta_blit.c index a41fe42..1f9515a 100644 --- a/src/mesa/drivers/common/meta_blit.c +++ b/src/mesa/drivers/common/meta_blit.c @@ -74,20 +74,25 @@ setup_glsl_msaa_blit_scaled_shader(struct gl_context *ctx, const char *vs_source; const char *sampler_array_suffix = ""; const char *texcoord_type = "vec2"; - float y_scale; + float x_scale, y_scale; enum blit_msaa_shader shader_index; assert(src_rb); samples = MAX2(src_rb->NumSamples, 1); - y_scale = samples * 0.5; + + if (samples == 16) + x_scale = 4.0; + else + x_scale = 2.0; + y_scale = samples / x_scale; /* We expect only power of 2 samples in source multisample buffer. */ assert(samples > 0 && _mesa_is_pow_two(samples)); while (samples >> (shader_offset + 1)) { shader_offset++; } - /* Update the assert if we plan to support more than 8X MSAA. */ - assert(shader_offset > 0 && shader_offset < 4); + /* Update the assert if we plan to support more than 16X MSAA. */ + assert(shader_offset > 0 && shader_offset <= 4); assert(target == GL_TEXTURE_2D_MULTISAMPLE || target == GL_TEXTURE_2D_MULTISAMPLE_ARRAY); @@ -132,6 +137,10 @@ setup_glsl_msaa_blit_scaled_shader(struct gl_context *ctx, sample_number = "sample_map[int(2 * fract(coord.x) + 8 * fract(coord.y))]"; sample_map = ctx->Const.SampleMap8x; break; + case 16: + sample_number = "sample_map[int(4 * fract(coord.x) + 16 * fract(coord.y))]"; + sample_map = ctx->Const.SampleMap16x; + break; default: sample_number = NULL; sample_map = NULL; @@ -178,9 +187,9 @@ setup_glsl_msaa_blit_scaled_shader(struct gl_context *ctx, "{\n" "%s" " vec2 interp;\n" - " const vec2 scale = vec2(2.0f, %ff);\n" - " const vec2 scale_inv = vec2(0.5f, %ff);\n" - " const vec2 s_0_offset = vec2(0.25f, %ff);\n" + " const vec2 scale = vec2(%ff, %ff);\n" + " const vec2 scale_inv = vec2(%ff, %ff);\n" + " const vec2 s_0_offset = vec2(%ff, %ff);\n" " vec2 s_0_coord, s_1_coord, s_2_coord, s_3_coord;\n" " vec4 s_0_color, s_1_color, s_2_color, s_3_color;\n" " vec4 x_0_color, x_1_color;\n" @@ -214,9 +223,9 @@ setup_glsl_msaa_blit_scaled_shader(struct gl_context *ctx, sampler_array_suffix, texcoord_type, sample_map_expr, - y_scale, - 1.0f / y_scale, - 1.0f / samples, + x_scale, y_scale, + 1.0f / x_scale, 1.0f / y_scale, + 0.5f / x_scale, 0.5f / y_scale, texel_fetch_macro); _mesa_meta_compile_and_link_program(ctx, vs_source, fs_source, name, diff --git a/src/mesa/drivers/dri/i965/gen6_multisample_state.c b/src/mesa/drivers/dri/i965/gen6_multisample_state.c index 49c6eba..8eb620d 100644 --- a/src/mesa/drivers/dri/i965/gen6_multisample_state.c +++ b/src/mesa/drivers/dri/i965/gen6_multisample_state.c @@ -91,6 +91,17 @@ gen6_get_sample_position(struct gl_context *ctx, * | 6 | 7 | | 7 | 1 | * --------- --------- * + * 16X MSAA sample index layout 16x MSAA sample number layout + * ----------------- ----------------- + * | 0 | 1 | 2 | 3 | |15 |10 | 9 | 7 | + * ----------------- ----------------- + * | 4 | 5 | 6 | 7 | | 4 | 1 | 3 |13 | + * ----------------- ----------------- + * | 8 | 9 |10 |11 | |12 | 2 | 0 | 6 | + * ----------------- ----------------- + * |12 |13 |14 |15 | |11 | 8 | 5 |14 | + * ----------------- ----------------- + * * A sample map is used to map sample indices to sample numbers. */ void @@ -99,10 +110,13 @@ gen6_set_sample_maps(struct gl_context *ctx) uint8_t map_2x[2] = {0, 1}; uint8_t map_4x[4] = {0, 1, 2, 3}; uint8_t map_8x[8] = {5, 2, 4, 6, 0, 3, 7, 1}; + uint8_t map_16x[16] = { 15, 10, 9, 7, 4, 1, 3, 13, + 12, 2, 0, 6, 11, 8, 5, 14 }; memcpy(ctx->Const.SampleMap2x, map_2x, sizeof(map_2x)); memcpy(ctx->Const.SampleMap4x, map_4x, sizeof(map_4x)); memcpy(ctx->Const.SampleMap8x, map_8x, sizeof(map_8x)); + memcpy(ctx->Const.SampleMap16x, map_16x, sizeof(map_16x)); } /** diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h index fac45aa..e0a06f4 100644 --- a/src/mesa/main/mtypes.h +++ b/src/mesa/main/mtypes.h @@ -3550,11 +3550,24 @@ struct gl_constants * below: * SampleMap8x = {a, b, c, d, e, f, g, h}; * - * Follow the logic for other sample counts. + * Follow the logic for sample counts 2-8. + * + * For 16x the sample indices layout as a 4x4 grid as follows: + * + * ----------------- + * | 0 | 1 | 2 | 3 | + * ----------------- + * | 4 | 5 | 6 | 7 | + * ----------------- + * | 8 | 9 |10 |11 | + * ----------------- + * |12 |13 |14 |15 | + * ----------------- */ uint8_t SampleMap2x[2]; uint8_t SampleMap4x[4]; uint8_t SampleMap8x[8]; + uint8_t SampleMap16x[16]; /** GL_ARB_shader_atomic_counters */ GLuint MaxAtomicBufferBindings; -- 1.9.3 _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev