1# [description]
2# Verify that gl_ClipDistance works properly when used as a function
3# "inout" parameter.
4#
5# This test initializes gl_ClipDistance with the negative of the
6# desired clipping values, then calls a function which negates each
7# element of the array.
8#
9# Then it checks two things:
10# - That the desired values wound up in gl_ClipDistance
11# - That clipping occurred as expected
12#
13# To check that clipping occurred as expected, the 8 gl_ClipDistance
14# values are used to clip a rectangle to an octagon shape.
15#
16# The octagon is centered at (0.5, 0.5), and has a small radius
17# (distance from center to perpendicular edge) of 0.4.
18
19[require]
20GLSL >= 1.30
21
22[vertex shader]
23#version 130
24
25out float gl_ClipDistance[8];
26
27void foo(inout float clip_distance[8])
28{
29	for (int i = 0; i < 8; ++i) {
30		clip_distance[i] = -clip_distance[i];
31	}
32}
33
34void main(void)
35{
36	gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;
37
38	// Compute 2D cordinates relative to a center point of (0.5,
39	// 0.5).
40	vec2 coord = gl_Vertex.xy - vec2(0.5, 0.5);
41
42	float desired_values[8];
43
44	for (int i = 0; i < 8; ++i) {
45		// Compute a unit vector in the direction i*45deg from
46		// the x axis.
47		float angle = i*(3.141592653589793/4);
48		vec2 u = vec2(cos(angle), sin(angle));
49
50		// Reject points whose 2D coordinate, projected onto
51		// that unit vector, is greater than 0.4.
52		desired_values[i] = 0.4 - dot(u, coord);
53		gl_ClipDistance[i] = -desired_values[i];
54	}
55
56	foo(gl_ClipDistance);
57
58	for (int i = 0; i < 8; ++i) {
59		if (desired_values[i] != gl_ClipDistance[i]) {
60			gl_FrontColor = vec4(1.0, 0.0, 0.0, 1.0);
61			return;
62		}
63	}
64	gl_FrontColor = vec4(0.0, 1.0, 0.0, 1.0);
65}
66
67[fragment shader]
68#version 130
69void main(void)
70{
71	gl_FragColor = gl_Color;
72}
73
74[test]
75clear color 0.0 0.0 0.0 0.0
76clear
77ortho 0 1 0 1
78enable GL_CLIP_PLANE0
79enable GL_CLIP_PLANE1
80enable GL_CLIP_PLANE2
81enable GL_CLIP_PLANE3
82enable GL_CLIP_PLANE4
83enable GL_CLIP_PLANE5
84enable GL_CLIP_PLANE6
85enable GL_CLIP_PLANE7
86draw rect 0.0 0.0 1.0 1.0
87
88# Test points inside each octagon edge
89relative probe rgba (0.850, 0.500) (0.0, 1.0, 0.0, 1.0)
90relative probe rgba (0.747, 0.747) (0.0, 1.0, 0.0, 1.0)
91relative probe rgba (0.500, 0.850) (0.0, 1.0, 0.0, 1.0)
92relative probe rgba (0.253, 0.747) (0.0, 1.0, 0.0, 1.0)
93relative probe rgba (0.150, 0.500) (0.0, 1.0, 0.0, 1.0)
94relative probe rgba (0.253, 0.253) (0.0, 1.0, 0.0, 1.0)
95relative probe rgba (0.500, 0.150) (0.0, 1.0, 0.0, 1.0)
96relative probe rgba (0.747, 0.253) (0.0, 1.0, 0.0, 1.0)
97
98# Test points outside each octagon edge
99relative probe rgba (0.950, 0.500) (0.0, 0.0, 0.0, 0.0)
100relative probe rgba (0.818, 0.818) (0.0, 0.0, 0.0, 0.0)
101relative probe rgba (0.500, 0.950) (0.0, 0.0, 0.0, 0.0)
102relative probe rgba (0.182, 0.818) (0.0, 0.0, 0.0, 0.0)
103relative probe rgba (0.050, 0.500) (0.0, 0.0, 0.0, 0.0)
104relative probe rgba (0.182, 0.182) (0.0, 0.0, 0.0, 0.0)
105relative probe rgba (0.500, 0.050) (0.0, 0.0, 0.0, 0.0)
106relative probe rgba (0.818, 0.182) (0.0, 0.0, 0.0, 0.0)
107