Fixed atan corner case
atan(0, <negative>) was returning 0 instead of PI. Did a simple
fix in the arctan() function and added an associated unit test.
Change-Id: Idbbdaf099b5104e3aaa2868ca8fd806c6c735981
Reviewed-on: https://swiftshader-review.googlesource.com/18868
Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
diff --git a/src/Shader/ShaderCore.cpp b/src/Shader/ShaderCore.cpp
index 883131c..338605c 100644
--- a/src/Shader/ShaderCore.cpp
+++ b/src/Shader/ShaderCore.cpp
@@ -402,14 +402,13 @@
Float4 y0 = Abs(y);
// Rotate to right quadrant when in left quadrant
- Int4 non_zero_y = CmpNEQ(y0, Float4(0.0f));
- Int4 Q = CmpLT(x0, Float4(0.0f)) & non_zero_y;
+ Int4 Q = CmpLT(x0, Float4(0.0f));
theta += As<Float4>(Q & As<Int4>(half_pi));
Float4 x1 = As<Float4>((Q & As<Int4>(y0)) | (~Q & As<Int4>(x0))); // FIXME: Vector select
Float4 y1 = As<Float4>((Q & As<Int4>(-x0)) | (~Q & As<Int4>(y0))); // FIXME: Vector select
// Mirror to first octant when in second octant
- Int4 O = CmpNLT(y1, x1) & non_zero_y;
+ Int4 O = CmpNLT(y1, x1);
Float4 x2 = As<Float4>((O & As<Int4>(y1)) | (~O & As<Int4>(x1))); // FIXME: Vector select
Float4 y2 = As<Float4>((O & As<Int4>(x1)) | (~O & As<Int4>(y1))); // FIXME: Vector select
@@ -417,7 +416,7 @@
Int4 zero_x = CmpEQ(x2, Float4(0.0f));
Int4 inf_y = IsInf(y2); // Since x2 >= y2, this means x2 == y2 == inf, so we use 45 degrees or pi/4
Float4 atan2_theta = arctan_01(y2 / x2, pp);
- theta += As<Float4>((~zero_x & ~inf_y & non_zero_y & ((O & As<Int4>(half_pi - atan2_theta)) | (~O & (As<Int4>(atan2_theta))))) | // FIXME: Vector select
+ theta += As<Float4>((~zero_x & ~inf_y & ((O & As<Int4>(half_pi - atan2_theta)) | (~O & (As<Int4>(atan2_theta))))) | // FIXME: Vector select
(inf_y & As<Int4>(quarter_pi)));
// Recover loss of precision for tiny theta angles
diff --git a/tests/unittests/unittests.cpp b/tests/unittests/unittests.cpp
index 1418e43..3132258 100644
--- a/tests/unittests/unittests.cpp
+++ b/tests/unittests/unittests.cpp
@@ -258,9 +258,12 @@
GLint posLoc = glGetAttribLocation(program, "position");
EXPECT_GLENUM_EQ(GL_NONE, glGetError());
- GLint location = glGetUniformLocation(program, textureName);
- ASSERT_NE(-1, location);
- glUniform1i(location, 0);
+ if(textureName)
+ {
+ GLint location = glGetUniformLocation(program, textureName);
+ ASSERT_NE(-1, location);
+ glUniform1i(location, 0);
+ }
float vertices[18] = { -1.0f, 1.0f, 0.5f,
-1.0f, -1.0f, 0.5f,
@@ -368,6 +371,60 @@
Uninitialize();
}
+// Test sampling from a sampler in a struct as a function argument
+TEST_F(SwiftShaderTest, AtanCornerCases)
+{
+ Initialize(3, false);
+
+ const std::string vs =
+ "#version 300 es\n"
+ "in vec4 position;\n"
+ "void main()\n"
+ "{\n"
+ " gl_Position = vec4(position.xy, 0.0, 1.0);\n"
+ "}\n";
+
+ const std::string fs =
+ "#version 300 es\n"
+ "precision mediump float;\n"
+ "const float kPI = 3.14159265358979323846;"
+ "uniform float positive_value;\n"
+ "uniform float negative_value;\n"
+ "out vec4 fragColor;\n"
+ "void main()\n"
+ "{\n"
+ " // Should yield vec4(0, pi, pi/2, -pi/2)\n"
+ " vec4 result = atan(vec4(0.0, 0.0, positive_value, negative_value),\n"
+ " vec4(positive_value, negative_value, 0.0, 0.0));\n"
+ " fragColor = (result / vec4(kPI)) + vec4(0.5, -0.5, 0.0, 1.0) + vec4(0.5 / 255.0);\n"
+ "}\n";
+
+ const ProgramHandles ph = createProgram(vs, fs);
+
+ glUseProgram(ph.program);
+ GLint positive_value = glGetUniformLocation(ph.program, "positive_value");
+ ASSERT_NE(-1, positive_value);
+ GLint negative_value = glGetUniformLocation(ph.program, "negative_value");
+ ASSERT_NE(-1, negative_value);
+ glUniform1f(positive_value, 1.0);
+ glUniform1f(negative_value, -1.0);
+
+ glClearColor(0.0, 0.0, 0.0, 0.0);
+ glClear(GL_COLOR_BUFFER_BIT);
+ EXPECT_GLENUM_EQ(GL_NONE, glGetError());
+
+ drawQuad(ph.program, nullptr);
+
+ deleteProgram(ph);
+
+ unsigned char grey[4] = { 128, 128, 128, 128 };
+ compareColor(grey);
+
+ EXPECT_GLENUM_EQ(GL_NONE, glGetError());
+
+ Uninitialize();
+}
+
// Note: GL_ARB_texture_rectangle is part of gl2extchromium.h in the Chromium repo
// GL_ARB_texture_rectangle
#ifndef GL_ARB_texture_rectangle
