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[require]
GLSL >= 1.20
[vertex shader passthrough]
[fragment shader]
#version 120
const vec4 red = vec4(1., 0., 0., 1.);
const vec4 green = vec4(0., 1., 0., 1.);
const vec4 blue = vec4(0., 0., 1., 1.);
void main()
{
int i = 17;
int j = -2;
do
// Page 45 of the GLSL 4.60.7 specification says:
//
// The body of a do-while loop introduces a new scope lasting only
// between the do and while (not including the while test
// expression), whether or not the body is simple or compound
//
// Earlier versions of the spec have similar wording. Any changes
// here are taken to be clarifications rather than intentional
// version-related changes.
int i = (j++, 0);
while (i <= 0 && j < 3);
if (j == -1)
// Correct result. Loop executed once and `j` was incremented once.
gl_FragColor = green;
else if (j == 2)
// This means `i` in the loop test incorrectly came from inside the
// loop and the sequence operator produced the wrong result (i.e., j++
// instead of 0). The loop terminated when `i` was 1, and, due to
// post-increment, `j` is 2.
gl_FragColor = blue;
else
// Mostly likely cause is `i` in the loop test is the `i` from inside
// the loop when it should be the `i` from outside the loop.
gl_FragColor = red;
}
[test]
clear color 0.0 0.0 0.0 0.0
clear
draw rect -1 -1 2 2
probe all rgba 0.0 1.0 0.0 1.0
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