[vertex] layout(location=0) in highp vec4 vertex_attrib; void main() { gl_Position = vertex_attrib; } [fragment] uniform highp sampler2D source_exposure; //texunit:0 #ifdef EXPOSURE_BEGIN uniform highp ivec2 source_render_size; uniform highp ivec2 target_size; #endif #ifdef EXPOSURE_END uniform highp sampler2D prev_exposure; //texunit:1 uniform highp float exposure_adjust; uniform highp float min_luminance; uniform highp float max_luminance; #endif layout(location = 0) out highp float exposure; void main() { #ifdef EXPOSURE_BEGIN ivec2 src_pos = ivec2(gl_FragCoord.xy)*source_render_size/target_size; #if 1 //more precise and expensive, but less jittery ivec2 next_pos = ivec2(gl_FragCoord.xy+ivec2(1))*source_render_size/target_size; next_pos = max(next_pos,src_pos+ivec2(1)); //so it at least reads one pixel highp vec3 source_color=vec3(0.0); for(int i=src_pos.x;i<next_pos.x;i++) { for(int j=src_pos.y;j<next_pos.y;j++) { source_color += texelFetch(source_exposure,ivec2(i,j),0).rgb; } } source_color/=float( (next_pos.x-src_pos.x)*(next_pos.y-src_pos.y) ); #else highp vec3 source_color = texelFetch(source_exposure,src_pos,0).rgb; #endif exposure = max(source_color.r,max(source_color.g,source_color.b)); #else ivec2 coord = ivec2(gl_FragCoord.xy); exposure = texelFetch(source_exposure,coord*3+ivec2(0,0),0).r; exposure += texelFetch(source_exposure,coord*3+ivec2(1,0),0).r; exposure += texelFetch(source_exposure,coord*3+ivec2(2,0),0).r; exposure += texelFetch(source_exposure,coord*3+ivec2(0,1),0).r; exposure += texelFetch(source_exposure,coord*3+ivec2(1,1),0).r; exposure += texelFetch(source_exposure,coord*3+ivec2(2,1),0).r; exposure += texelFetch(source_exposure,coord*3+ivec2(0,2),0).r; exposure += texelFetch(source_exposure,coord*3+ivec2(1,2),0).r; exposure += texelFetch(source_exposure,coord*3+ivec2(2,2),0).r; exposure *= (1.0/9.0); #ifdef EXPOSURE_END #ifdef EXPOSURE_FORCE_SET //will stay as is #else highp float prev_lum = texelFetch(prev_exposure,ivec2(0,0),0).r; //1 pixel previous exposure exposure = clamp( prev_lum + (exposure-prev_lum)*exposure_adjust,min_luminance,max_luminance); #endif //EXPOSURE_FORCE_SET #endif //EXPOSURE_END #endif //EXPOSURE_BEGIN }