From: Steinar H. Gunderson <sgunderson@bigfoot.com>
Date: Wed, 22 Nov 2017 19:13:46 +0000 (+0100)
Subject: Support sqrt-transformed intermediates with compute shaders.
X-Git-Tag: 1.6.0~42
X-Git-Url: https://git.sesse.net/?p=movit;a=commitdiff_plain;h=beef8c4b242dd9e073f04b80539a10295417ced5;ds=sidebyside

Support sqrt-transformed intermediates with compute shaders.
---

diff --git a/effect_chain_test.cpp b/effect_chain_test.cpp
index 2140354..63f574b 100644
--- 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 3ece901..16197a6 100644
--- 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);
 }