first pass

assets/minecraft/shaders/core/lightmap.fsh

@@ -0,0 +1,66 @@
+#version 330
+
+layout(std140) uniform LightmapInfo {
+    float SkyFactor;
+    float BlockFactor;
+    float NightVisionFactor;
+    float DarknessScale;
+    float BossOverlayWorldDarkeningFactor;
+    float BrightnessFactor;
+    vec3 BlockLightTint;
+    vec3 SkyLightColor;
+    vec3 AmbientColor;
+    vec3 NightVisionColor;
+} lightmapInfo;
+
+in vec2 texCoord;
+
+out vec4 fragColor;
+
+float get_brightness(float level) {
+    return level / (4.0 - 3.0 * level);
+}
+
+vec3 notGamma(vec3 color) {
+    float maxComponent = max(max(color.x, color.y), color.z);
+    float maxInverted = 1.0f - maxComponent;
+    float maxScaled = 1.0f - maxInverted * maxInverted * maxInverted * maxInverted;
+    return color * (maxScaled / maxComponent);
+}
+
+float parabolicMixFactor(float level) {
+    return (2.0 * level - 1.0) * (2.0 * level - 1.0);
+}
+
+void main() {
+    // Calculate block and sky brightness levels based on texture coordinates
+    float block_level = floor(texCoord.x * 16) / 15;
+    float sky_level = floor(texCoord.y * 16) / 15;
+
+    float block_brightness = get_brightness(block_level) * lightmapInfo.BlockFactor;
+    float sky_brightness = get_brightness(sky_level) * lightmapInfo.SkyFactor;
+
+    // Calculate ambient color with or without night vision
+    vec3 nightVisionColor = lightmapInfo.NightVisionColor * lightmapInfo.NightVisionFactor;
+    vec3 color = max(lightmapInfo.AmbientColor, nightVisionColor);
+
+    // Add sky light
+    color += lightmapInfo.SkyLightColor * sky_brightness;
+
+    // Add block light
+    vec3 BlockLightColor = mix(lightmapInfo.BlockLightTint, vec3(1.0), 0.9 * parabolicMixFactor(block_level));
+    color += BlockLightColor * block_brightness;
+
+    // Apply boss overlay darkening effect
+    color = mix(color, color * vec3(0.7, 0.6, 0.6), lightmapInfo.BossOverlayWorldDarkeningFactor);
+
+    // Apply darkness effect scale
+    color = color - vec3(lightmapInfo.DarknessScale);
+
+    // Apply brightness
+    color = clamp(color, 0.0, 1.0);
+    vec3 notGamma = notGamma(color);
+    color = mix(color, notGamma, lightmapInfo.BrightnessFactor);
+
+    fragColor = vec4(color, 1.0);
+}