Add stubs for GL_OES_fbo_render_mipmap.

BUG=angle:905

Change-Id: Idd4964bd2d9d07cd98137770e1cc57397f1dd3a6
Reviewed-on: https://chromium-review.googlesource.com/263762
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>
diff --git a/src/tests/end2end_tests/FramebufferRenderMipmapTest.cpp b/src/tests/end2end_tests/FramebufferRenderMipmapTest.cpp
new file mode 100644
index 0000000..1944c67
--- /dev/null
+++ b/src/tests/end2end_tests/FramebufferRenderMipmapTest.cpp
@@ -0,0 +1,181 @@
+#include "ANGLETest.h"
+
+// Use this to select which configurations (e.g. which renderer, which GLES major version) these tests should be run against.
+ANGLE_TYPED_TEST_CASE(FramebufferRenderMipmapTest, ES2_D3D9, ES2_D3D11, ES3_D3D11);
+
+template<typename T>
+class FramebufferRenderMipmapTest : public ANGLETest
+{
+protected:
+    FramebufferRenderMipmapTest() : ANGLETest(T::GetGlesMajorVersion(), T::GetPlatform())
+    {
+        setWindowWidth(256);
+        setWindowHeight(256);
+        setConfigRedBits(8);
+        setConfigGreenBits(8);
+        setConfigBlueBits(8);
+        setConfigAlphaBits(8);
+    }
+
+    virtual void SetUp()
+    {
+        ANGLETest::SetUp();
+
+        const std::string vsSource = SHADER_SOURCE
+        (
+            attribute highp vec4 position;
+            void main(void)
+            {
+                gl_Position = position;
+            }
+        );
+
+        const std::string fsSource = SHADER_SOURCE
+        (
+            uniform highp vec4 color;
+            void main(void)
+            {
+                gl_FragColor = color;
+            }
+        );
+
+        mProgram = CompileProgram(vsSource, fsSource);
+        if (mProgram == 0)
+        {
+            FAIL() << "shader compilation failed.";
+        }
+
+        mColorLocation = glGetUniformLocation(mProgram, "color");
+
+        glUseProgram(mProgram);
+
+        glClearColor(0, 0, 0, 0);
+        glClearDepthf(0.0);
+        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+        glEnable(GL_BLEND);
+        glDisable(GL_DEPTH_TEST);
+
+        ASSERT_GL_NO_ERROR();
+    }
+
+    virtual void TearDown()
+    {
+        glDeleteProgram(mProgram);
+
+        ANGLETest::TearDown();
+    }
+
+    GLuint mProgram;
+    GLint mColorLocation;
+};
+
+// Validate that if we are in ES3 or GL_OES_fbo_render_mipmap exists, there are no validation errors
+// when using a non-zero level in glFramebufferTexture2D.
+TYPED_TEST(FramebufferRenderMipmapTest, Validation)
+{
+    bool renderToMipmapSupported = extensionEnabled("GL_OES_fbo_render_mipmap") || getClientVersion() > 2;
+
+    GLuint tex = 0;
+    glGenTextures(1, &tex);
+    glBindTexture(GL_TEXTURE_2D, tex);
+
+    const size_t levels = 5;
+    for (size_t i = 0; i < levels; i++)
+    {
+        size_t size = 1 << ((levels - 1) - i);
+        glTexImage2D(GL_TEXTURE_2D, i, GL_RGBA, size, size, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
+    }
+
+    EXPECT_GL_NO_ERROR();
+
+    GLuint fbo = 0;
+    glGenFramebuffers(1, &fbo);
+    glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+    EXPECT_GL_NO_ERROR();
+
+    for (size_t i = 0; i < levels; i++)
+    {
+        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, tex, i);
+
+        if (i > 0 && !renderToMipmapSupported)
+        {
+            EXPECT_GL_ERROR(GL_INVALID_VALUE);
+        }
+        else
+        {
+            EXPECT_GL_NO_ERROR();
+            EXPECT_EQ(glCheckFramebufferStatus(GL_FRAMEBUFFER), GLenum(GL_FRAMEBUFFER_COMPLETE));
+        }
+    }
+
+    glDeleteFramebuffers(1, &fbo);
+    glDeleteTextures(1, &tex);
+}
+
+// Render to various levels of a texture and check that they have the correct color data via ReadPixels
+TYPED_TEST(FramebufferRenderMipmapTest, RenderToMipmap)
+{
+    bool renderToMipmapSupported = extensionEnabled("GL_OES_fbo_render_mipmap") || getClientVersion() > 2;
+    if (!renderToMipmapSupported)
+    {
+        std::cout << "Test skipped because GL_OES_fbo_render_mipmap or ES3 is not available." << std::endl;
+        return;
+    }
+
+    const GLfloat levelColors[] =
+    {
+        1.0f, 0.0f, 0.0f, 1.0f,
+        0.0f, 1.0f, 0.0f, 1.0f,
+        0.0f, 0.0f, 1.0f, 1.0f,
+        1.0f, 1.0f, 0.0f, 1.0f,
+        1.0f, 0.0f, 1.0f, 1.0f,
+        0.0f, 1.0f, 1.0f, 1.0f,
+    };
+    const size_t testLevels = ArraySize(levelColors) / 4;
+
+    GLuint tex = 0;
+    glGenTextures(1, &tex);
+    glBindTexture(GL_TEXTURE_2D, tex);
+
+    for (size_t i = 0; i < testLevels; i++)
+    {
+        size_t size = 1 << ((testLevels - 1) - i);
+        glTexImage2D(GL_TEXTURE_2D, i, GL_RGBA, size, size, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
+    }
+
+    EXPECT_GL_NO_ERROR();
+
+    GLuint fbo = 0;
+    glGenFramebuffers(1, &fbo);
+    glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+    EXPECT_GL_NO_ERROR();
+
+    // Render to the levels of the texture with different colors
+    for (size_t i = 0; i < testLevels; i++)
+    {
+        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, tex, i);
+        EXPECT_GL_NO_ERROR();
+
+        glUseProgram(mProgram);
+        glUniform4fv(mColorLocation, 1, levelColors + (i * 4));
+
+        drawQuad(mProgram, "position", 0.5f);
+        EXPECT_GL_NO_ERROR();
+    }
+
+    // Test that the levels of the texture are correct
+    for (size_t i = 0; i < testLevels; i++)
+    {
+        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, tex, i);
+        EXPECT_GL_NO_ERROR();
+
+        const GLfloat *color = levelColors + (i * 4);
+        EXPECT_PIXEL_EQ(0, 0, color[0] * 255, color[1] * 255, color[2] * 255, color[3] * 255);
+    }
+
+    glDeleteFramebuffers(1, &fbo);
+    glDeleteTextures(1, &tex);
+
+    EXPECT_GL_NO_ERROR();
+}