Preprocessor support

[stefan1000]

Since glslx doesn't support preprocessing, how to check e.g. if highp is available in a fragment shader ?

#ifndef GL_FRAGMENT_PRECISION_HIGH
precision mediump float;
#else
precision highp float;
#endif

[bramtechs]

Usage of #define is detected as a syntax error.

<stdin>:7:1: error: Unexpected PRAGMA
#define ITERATIONS 8

#version 100
precision highp float;

#define ITERATIONS 8

varying vec2 fragTexCoord;
varying vec4 fragColor;

uniform sampler2D texture0;
uniform vec4 colDiffuse;

uniform sampler2D texture1;
uniform float power;

float map(float value, float min1, float max1, float min2, float max2) {
    return min2 + (value - min1) * (max2 - min2) / (max1 - min1);
}

int modulo(int value, int interval) {
	while (value >= interval) {
		value -= interval;
	}
	return value;
}

vec2 getPos(vec2 uv, float scale, int iter) {
    float shuffle = float(iter / 4);
    vec2 mapped = uv + vec2(shuffle * -5.4894, shuffle * 12.546);
    vec4 color = texture2D(texture1, mapped);

    float x = color[modulo(iter+0, 4)];
    float y = color[modulo(iter+1, 4)];

    return uv + vec2(x,y) * scale;
}

void main() {
    float scale = map(power, 0.0, 1.0, 0.0, 0.12);

    vec4 col = vec4(0.0, 0.0, 0.0, 0.0);
    for (int i = 0; i < ITERATIONS; i++) {
        col += texture2D(texture0, getPos(fragTexCoord, scale, i));
    }

    vec4 outputColor = col / float(ITERATIONS);
    gl_FragColor = vec4(outputColor.xyz, 1.0);
}

Workaround is just declaring a variable. ¯\(ツ)/¯

int ITERATIONS = 8;