Support sqrt-transformed intermediates with compute shaders.

diff --git a/effect_chain_test.cpp b/effect_chain_test.cpp
index 21403541827a4f48d630e8dee85403b6dc99b696..63f574be615d2bb80ccbadfd9b56328173470db3 100644 (file)
--- a/effect_chain_test.cpp
+++ b/effect_chain_test.cpp
@@ -1304,6 +1304,21 @@ TEST(EffectChainTest, StringStreamLocalesWork) {
        free(saved_locale);
 }
 
+// An effect that does nothing, but as a compute shader.
+class IdentityComputeEffect : public Effect {
+public:
+       IdentityComputeEffect() {}
+       virtual string effect_type_id() const { return "IdentityComputeEffect"; }
+       virtual bool is_compute_shader() const { return true; }
+       string output_fragment_shader() { return read_file("identity.comp"); }
+};
+
+class WithAndWithoutComputeShaderTest : public testing::TestWithParam<string> {
+};
+INSTANTIATE_TEST_CASE_P(WithAndWithoutComputeShaderTest,
+                        WithAndWithoutComputeShaderTest,
+                        testing::Values("fragment", "compute"));
+
 TEST(EffectChainTest, sRGBIntermediate) {
        float data[] = {
                0.0f, 0.5f, 0.0f, 1.0f,
@@ -1371,7 +1386,7 @@ TEST(EffectChainTest, Linear10bitIntermediateAccuracy) {
        expect_equal(linear_data, out_data, size, 1, 7.5e-3, 2e-5);
 }
 
-TEST(EffectChainTest, SquareRoot10bitIntermediateAccuracy) {
+TEST_P(WithAndWithoutComputeShaderTest, SquareRoot10bitIntermediateAccuracy) {
        // Note that we do the comparison in sRGB space, which is what we
        // typically would want; however, we do the sRGB conversion ourself
        // to avoid compounding errors from shader conversions into the
@@ -1386,7 +1401,11 @@ TEST(EffectChainTest, SquareRoot10bitIntermediateAccuracy) {
 
        EffectChainTester tester(data, size, 1, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_LINEAR, GL_RGBA32F);
        tester.get_chain()->set_intermediate_format(GL_RGB10_A2, SQUARE_ROOT_FRAMEBUFFER_TRANSFORMATION);
-       tester.get_chain()->add_effect(new IdentityEffect());
+       if (GetParam() == "compute") {
+               tester.get_chain()->add_effect(new IdentityComputeEffect());
+       } else {
+               tester.get_chain()->add_effect(new IdentityEffect());
+       }
        tester.get_chain()->add_effect(new BouncingIdentityEffect());
        tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
 
@@ -1467,15 +1486,6 @@ TEST(EffectChainTest, ProgramsAreClonedForMultipleThreads) {
        expect_equal(data, out_data, 3, 2);
 }
 
-// An effect that does nothing, but as a compute shader.
-class IdentityComputeEffect : public Effect {
-public:
-       IdentityComputeEffect() {}
-       virtual string effect_type_id() const { return "IdentityComputeEffect"; }
-       virtual bool is_compute_shader() const { return true; }
-       string output_fragment_shader() { return read_file("identity.comp"); }
-};
-
 TEST(ComputeShaderTest, Identity) {
        float data[] = {
                0.0f, 0.25f, 0.3f,

diff --git a/footer.comp b/footer.comp
index 3ece901eb00e8de9fe4f1200101a19162b2b08fc..16197a63200019396c20661bc0edbb8128fad206 100644 (file)
--- a/footer.comp
+++ b/footer.comp
@@ -1,3 +1,10 @@
+// GLSL is pickier than the C++ preprocessor in if-testing for undefined
+// tokens; do some fixups here to keep it happy.
+
+#ifndef SQUARE_ROOT_TRANSFORMATION
+#define SQUARE_ROOT_TRANSFORMATION 0
+#endif
+
 void main()
 {
        INPUT();
@@ -10,10 +17,14 @@ vec4 tex2D(sampler2D s, vec2 coord)
 
 void cs_output(uvec2 coord, vec4 val)
 {
-       imageStore(outbuf, ivec2(coord), val);
+       cs_output(ivec2(coord), val);
 }
 
 void cs_output(ivec2 coord, vec4 val)
 {
+#if SQUARE_ROOT_TRANSFORMATION
+       // Make sure we don't give negative values to sqrt.
+       val.rgb = sqrt(max(val.rgb, 0.0));
+#endif
        imageStore(outbuf, coord, val);
 }