1 files changed, 98 insertions, 0 deletions
diff --git a/drivers/gles2/shaders/exposure.glsl b/drivers/gles2/shaders/exposure.glsl
new file mode 100644
index 0000000000..001b90a0f1
--- /dev/null
+++ b/drivers/gles2/shaders/exposure.glsl
@@ -0,0 +1,98 @@
+[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
+
+
+}
+
+