1 //
2 // Copyright 2020 The ANGLE Project Authors. All rights reserved.
3 // Use of this source code is governed by a BSD-style license that can be
4 // found in the LICENSE file.
5 //
6
7 // Test that invokes a usecase where there is a feedback loop but the framebuffer
8 // depth attachment is only read from
9
10 #include "test_utils/ANGLETest.h"
11 #include "test_utils/gl_raii.h"
12
13 using namespace angle;
14
15 class ReadOnlyFeedbackLoopTest : public ANGLETest
16 {
17 protected:
ReadOnlyFeedbackLoopTest()18 ReadOnlyFeedbackLoopTest()
19 {
20 setWindowWidth(256);
21 setWindowHeight(256);
22 setConfigRedBits(8);
23 setConfigGreenBits(8);
24 setConfigBlueBits(8);
25 setConfigAlphaBits(8);
26 }
27
testSetUp()28 void testSetUp() override
29 {
30 glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
31 glClearDepthf(1.0f);
32 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
33 glDepthRangef(-1.0f, 1.0f);
34
35 glEnable(GL_BLEND);
36 glDisable(GL_DEPTH_TEST);
37
38 ASSERT_GL_NO_ERROR();
39 }
40 };
41
42 // Fill out a depth texture to specific values and use it both as a sampler and a depth texture
43 // with depth write disabled. This is to test a "read-only feedback loop" that needs to be
44 // supported to match industry standard.
TEST_P(ReadOnlyFeedbackLoopTest,DepthFeedbackLoop)45 TEST_P(ReadOnlyFeedbackLoopTest, DepthFeedbackLoop)
46 {
47 // TODO - Add support for readonly feedback loops (http://anglebug.com/4778)
48 ANGLE_SKIP_TEST_IF(true);
49
50 const GLuint width = getWindowWidth();
51 const GLuint height = getWindowHeight();
52
53 GLTexture colorTex;
54 GLTexture depthTex;
55 GLTexture finalTex;
56
57 GLFramebuffer gbufferFbo;
58 GLFramebuffer finalFbo;
59
60 ANGLE_GL_PROGRAM(colorFillProgram, essl1_shaders::vs::Simple(), essl1_shaders::fs::Red());
61 ANGLE_GL_PROGRAM(textureFillProgram, essl1_shaders::vs::Texture2D(),
62 essl1_shaders::fs::Texture2D());
63
64 glBindTexture(GL_TEXTURE_2D, colorTex);
65 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
66 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
67 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
68 EXPECT_GL_NO_ERROR();
69
70 glBindTexture(GL_TEXTURE_2D, depthTex);
71 glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, width, height, 0, GL_DEPTH_COMPONENT,
72 GL_UNSIGNED_INT, nullptr);
73 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
74 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
75 EXPECT_GL_NO_ERROR();
76
77 glBindFramebuffer(GL_FRAMEBUFFER, gbufferFbo);
78 EXPECT_GL_NO_ERROR();
79
80 // Attach a color and depth texture to the FBO
81 glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, colorTex, 0);
82 EXPECT_GL_NO_ERROR();
83 glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, depthTex, 0);
84 EXPECT_GL_NO_ERROR();
85
86 ASSERT_GLENUM_EQ(GL_FRAMEBUFFER_COMPLETE, glCheckFramebufferStatus(GL_FRAMEBUFFER));
87
88 // Set the color texture to blue and depth texture to 1.0f
89 glClearColor(0.0f, 0.0f, 1.0f, 1.0f);
90 glClearDepthf(1.0f);
91 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
92 ASSERT_GL_NO_ERROR();
93
94 // Enable Depth test with passing always to write depth.
95 glEnable(GL_DEPTH_TEST);
96 glDepthMask(GL_TRUE);
97 glDepthFunc(GL_ALWAYS);
98
99 // Fill the middle of the depth texture with 0.0f. while the border remains 1.0f as
100 // previously cleared.
101 const GLfloat depthValue = 0.0f;
102 drawQuad(colorFillProgram, essl1_shaders::PositionAttrib(), depthValue, 0.6f);
103
104 EXPECT_GL_NO_ERROR();
105
106 glBindTexture(GL_TEXTURE_2D, finalTex);
107 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
108 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
109 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
110 EXPECT_GL_NO_ERROR();
111
112 glBindFramebuffer(GL_FRAMEBUFFER, finalFbo);
113 EXPECT_GL_NO_ERROR();
114
115 // Enable Depth test without depth write.
116 glEnable(GL_DEPTH_TEST);
117 glDepthMask(GL_FALSE);
118 glDepthFunc(GL_GREATER);
119
120 glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, finalTex, 0);
121 EXPECT_GL_NO_ERROR();
122 glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, depthTex, 0);
123 EXPECT_GL_NO_ERROR();
124 ASSERT_GLENUM_EQ(GL_FRAMEBUFFER_COMPLETE, glCheckFramebufferStatus(GL_FRAMEBUFFER));
125
126 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
127
128 glBindTexture(GL_TEXTURE_2D, depthTex);
129
130 // Fill finalTex with values read from depthTex. This should work even though depthTex
131 // is also bound as the depth attachment, because depth write is disabled.
132 // The write to finalTex only succeeds for the middle region due to depth test.
133 drawQuad(textureFillProgram, essl1_shaders::PositionAttrib(), 0.7f, 1.0f);
134
135 // Copy finalTex to default framebuffer for verification. Depth values written in the first
136 // draw call are expected in the middle, while the clear value in the clear before the
137 // second draw call are expected at the border.
138 glBindFramebuffer(GL_FRAMEBUFFER, 0);
139 glDisable(GL_DEPTH_TEST);
140 glDepthMask(GL_FALSE);
141 glBindTexture(GL_TEXTURE_2D, finalTex);
142 drawQuad(textureFillProgram, essl1_shaders::PositionAttrib(), 0.0f, 1.0f);
143 EXPECT_GL_NO_ERROR();
144
145 GLint depthColorValue = (depthValue)*128 + 128;
146 EXPECT_EQ(depthColorValue, angle::ReadColor(width / 2, height / 2).R);
147 EXPECT_PIXEL_EQ(0, 0, 0, 0, 255, 255);
148 }
149
150 // Instantiate the test for ES2 and ES3.
151 ANGLE_INSTANTIATE_TEST_ES2_AND_ES3(ReadOnlyFeedbackLoopTest);
152