acae607703
This is required to avoid relying on complex sub-expression elimination in compilers, and generates cleaner code. The problem case is if a complex expression is used in an access chain, like: Composite comp = buffer[texture(...)]; vec4 a = comp.a + comp.b + comp.c; Before, we did not have common subexpression tracking for OpLoad/OpAccessChain, so we easily ended up with code like: vec4 a = buffer[texture(...)].a + buffer[texture(...)].b + buffer[texture(...)].c; A good compiler will optimize this, but we should not rely on it, and forcing texture(...) to a temporary also looks better. The solution is to add a vector "implied_expression_reads", which works similarly to expression_dependencies. We also need an extra mechanism in to_expression which lets us skip expression read checking and do it later. E.g. for expr -> access chain -> load, we should only trigger a read of expr when using the loaded expression.
30 lines
501 B
GLSL
30 lines
501 B
GLSL
#version 310 es
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precision mediump float;
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struct Foo
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{
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vec4 a;
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vec4 b;
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};
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layout(binding = 0) buffer UBO
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{
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vec4 results[1024];
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};
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layout(binding = 1) uniform highp isampler2D Buf;
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layout(location = 0) flat in int vIn;
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layout(location = 1) flat in int vIn2;
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layout(location = 0) out vec4 FragColor;
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void main()
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{
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ivec4 coords = texelFetch(Buf, ivec2(gl_FragCoord.xy), 0);
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vec4 foo = results[coords.x % 16];
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int c = vIn * vIn;
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int d = vIn2 * vIn2;
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FragColor = foo + foo + results[c + d];
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}
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