render: SSAO

internal/asset/shader.go

@@ -9,6 +9,16 @@ var (
 	//go:embed shader/world/shadowmap.vert
 	WorldShaderShadowmapVert string
 
+	//go:embed shader/world/ssao.frag
+	WorldShaderSSAOFrag string
+	//go:embed shader/world/ssao.vert
+	WorldShaderSSAOVert string
+
+	//go:embed shader/world/ssao_blur.frag
+	WorldShaderSSAOBlurFrag string
+	//go:embed shader/world/ssao_blur.vert
+	WorldShaderSSAOBlurVert string
+
 	//go:embed shader/world/geometry.frag
 	WorldShaderGeometryFrag string
 	//go:embed shader/world/geometry.vert

internal/asset/shader/world/geometry.frag

@@ -4,7 +4,7 @@ uniform sampler2D tex;
 
 in vec3 fragPosWorld;
 in float fragPosLightspaceZ;
-in float fragDepthNDC;
+in float fragDepthView;
 in vec2 fragTexCoord;
 in vec3 fragNormal;
 in float fragLight;
@@ -19,9 +19,9 @@ const float gamma = 2.2;
 void main() {
 
 	outputPosition.xyz = fragPosWorld;
-	outputPosition.w = fragPosLightspaceZ;
+	outputPosition.w = fragDepthView;
 	outputNormal.xyz = fragNormal;
-	outputNormal.w = fragDepthNDC;
+	outputNormal.w = fragPosLightspaceZ;
 	outputColor = texture(tex, fragTexCoord);
 	outputColor = vec4(pow(outputColor.rgb, vec3(gamma)), outputColor.a);
 }

internal/asset/shader/world/geometry.vert

@@ -14,7 +14,7 @@ layout (location = 3) in float light;
 
 out vec3 fragPosWorld;
 out float fragPosLightspaceZ;
-out float fragDepthNDC;
+out float fragDepthView;
 out vec2 fragTexCoord;
 out vec3 fragNormal;
 out float fragLight;
@@ -25,14 +25,16 @@ void main() {
 	fragNormal = normalize(normal);
 	fragLight = light;
 
-    gl_Position = projection * view * model * vec4(vert, 1);
-	fragDepthNDC = gl_Position.z / gl_Position.w;
-
 	vec4 pos4 = model * vec4(vert, 1);
 	fragPosWorld = pos4.xyz / pos4.w;
 	vec4 fragPosLightspace = lightspace * vec4(fragPosWorld, 1.0f);
 	fragPosLightspaceZ = fragPosLightspace.z / fragPosLightspace.w *0.5f + 0.5f;
 
+	vec4 posView  = view * pos4;
+	fragDepthView = posView.z;
+
+    gl_Position = projection * posView;
+
 	fragPosWorld -= viewPos;
 }
 

internal/asset/shader/world/lighting.frag

@@ -6,6 +6,8 @@ uniform vec3 viewPos;
 uniform vec3 sun;
 uniform vec4 fogColor;
 
+uniform sampler2D ssaoAmbient; // Ambient strength from SSAO pass
+
 // G-Buffers
 uniform sampler2D gPos;
 uniform sampler2D gNorm;
@@ -40,12 +42,12 @@ void loadGBuffer() {
 	fragNormal = fragGNormal.xyz;
 	if (fragNormal == vec3(0.0f, 0.0f, 0.0f))
 		discard;
+	fragPosLightspaceZ = fragGNormal.w;
 
-	gl_FragDepth = fragGNormal.w * 0.5 + 0.5;
 
 	vec4 fragGPos = texture(gPos, fragPosScreen);
 	fragPos = vec4(fragGPos.xyz + viewPos, 1.0f);
-	fragPosLightspaceZ = fragGPos.w;
+
 	fragColor = texture(gColor, fragPosScreen);
 
 	fragPosLightspace = lightspace * fragPos;
@@ -56,7 +58,7 @@ void main() {
 
 	loadGBuffer();
 
-	light = ambient;
+	light = ambient * texture(ssaoAmbient, fragPosScreen).r;
 
 	lightSun();
 

internal/asset/shader/world/ssao.frag

@@ -0,0 +1,78 @@
+#version 330
+
+#define SSAO_SAMPLE_COUNT 32
+const float radius = 0.5, bias = 0;
+
+uniform vec3 viewPos;
+uniform mat4 view, projection;
+uniform float time; // current time in seconds, for extra noise
+
+uniform sampler2D rand;
+uniform vec2      randSize; // in pixels
+
+// SSAO samples (normalized, in tangent space)
+layout (std140) uniform uboSamples {
+	vec3 samples[SSAO_SAMPLE_COUNT];
+};
+
+// G-Buffers
+uniform sampler2D gPos;
+uniform sampler2D gNorm;
+// Fragment information from G-Buffers
+vec3 fragPos; // World position
+vec3 fragNormal; // World normal
+float fragDepthView;
+
+
+in vec2 fragPosScreen;
+layout (location = 0) out float output;
+
+
+// A random number generator from the web.
+// https://stackoverflow.com/questions/12964279/whats-the-origin-of-this-glsl-rand-one-liner
+float whatever(vec2 co){
+  return fract(sin(dot(co.xy ,vec2(12.9898,78.233))) * 43758.5453);
+}
+
+
+void loadGBuffer() {
+	vec4 fragGNormal = texture(gNorm, fragPosScreen);
+	fragNormal = fragGNormal.xyz;
+	if (fragNormal == vec3(0.0f, 0.0f, 0.0f))
+		discard;
+
+	vec4 fragGPos = texture(gPos, fragPosScreen);
+	fragPos = fragGPos.xyz + viewPos;
+	fragDepthView = fragGPos.w;
+	gl_FragDepth = fragGPos.w * 0.5 + 0.5;
+}
+
+
+void main() {
+
+	loadGBuffer();
+
+	vec4 randval = texture(rand, gl_FragCoord.xy / randSize);
+
+	vec3 tangent   = normalize(randval.xyz - fragNormal*dot(randval.xyz, fragNormal));
+	vec3 bitangent = cross(fragNormal, tangent);
+	mat3 TBN       = mat3(tangent, bitangent, fragNormal);
+
+	float occlusion = 0;
+	for (int i = 0; i < SSAO_SAMPLE_COUNT; i++) {
+		vec3 samplePos = TBN * samples[i];
+		samplePos = fragPos + samplePos * radius;
+
+		vec4 viewpos = view * vec4(samplePos, 1.0);
+
+		vec4 ndcpos = projection * viewpos;
+		ndcpos.xyz /= ndcpos.w;
+
+		float sampleDepth = texture(gPos, ndcpos.xy*0.5 + 0.5).w;
+
+		float rangeCheck = smoothstep(0.0, 1.0, radius / abs(fragDepthView - sampleDepth));
+		occlusion       += (sampleDepth >= viewpos.z/viewpos.w + bias ? 1.0 : 0.0) * rangeCheck; 
+	}
+
+	output = 1.0 - (occlusion / SSAO_SAMPLE_COUNT);
+}

internal/asset/shader/world/ssao.vert

@@ -0,0 +1,12 @@
+#version 330
+
+layout (location = 0) in vec2 vert;
+layout (location = 1) in vec2 texCoord;
+
+out vec2 fragPosScreen;
+
+void main() {
+    gl_Position = vec4(vert, 0.0f, 1);
+	fragPosScreen = texCoord;
+}
+

internal/asset/shader/world/ssao_blur.frag

@@ -0,0 +1,20 @@
+#version 330
+
+uniform sampler2D input;
+uniform vec2 screenSize;
+
+
+in vec2 fragPosScreen;
+layout (location = 0) out float output;
+
+
+void main() {
+	output = 0;
+
+	for (int i = -3; i <= 3; i++)
+		for (int j = -3; j <= 3; j++)
+			output += texture(input, fragPosScreen + vec2(i, j) / screenSize).r;
+
+	output /= 49.0;
+}
+

internal/asset/shader/world/ssao_blur.vert

@@ -0,0 +1,12 @@
+#version 330
+
+layout (location = 0) in vec2 vert;
+layout (location = 1) in vec2 texCoord;
+
+out vec2 fragPosScreen;
+
+void main() {
+    gl_Position = vec4(vert, 0.0f, 1);
+	fragPosScreen = texCoord;
+}
+

internal/render/render_world.go

@@ -1,8 +1,14 @@
 package render
 
 import (
+	"errors"
+	"math/rand"
+	"time"
+	"unsafe"
+
 	"edgaru089.ml/go/gl01/internal/asset"
 	"edgaru089.ml/go/gl01/internal/io"
+	"edgaru089.ml/go/gl01/internal/util"
 	"edgaru089.ml/go/gl01/internal/util/itype"
 	"edgaru089.ml/go/gl01/internal/world"
 	"github.com/go-gl/gl/all-core/gl"
@@ -10,14 +16,22 @@ import (
 	"github.com/inkyblackness/imgui-go/v4"
 )
 
+const (
+	SSAOSampleCount = 32 // Number of samples in the SSAO pass. Must stay the same with ssao.frag
+)
+
 var (
 	ShadowmapSize = itype.Vec2i{6144, 6144} // Size of the shadow mapping
+	RandomSize    = itype.Vec2i{32, 32}     // Size of the random mapping
 )
 
 // WorldRenderer holds texture/shader resource and viewport
 // information for world rendering.
 type WorldRenderer struct {
 	lastDisplaySize itype.Vec2i
+	startTime       time.Time
+
+	texRand uint32 // random texture mapping, RGBA8 (0~1)
 
 	// Depth mapping pass
 	depthmap struct {
@@ -29,12 +43,27 @@ type WorldRenderer struct {
 	gbuffer struct {
 		fbo uint32 // The Framebuffer object.
 
-		// Textures. Position/Lightspace Depth;   Normal/Depth;  Diffuse Color/Specular Intensity.
+		// Textures. Position/Depth(View Space);   Normal/Lightspace Depth;  Diffuse Color/Specular Intensity.
 		pos, norm, color uint32
-		depth            uint32
+		depth            uint32  // Depth renderbuffer.
 		shader           *Shader // Geometry pass shaders.
 	}
 
+	// Screen-Space Ambient Occlusion (SSAO) pass
+	ssao struct {
+		fbo        uint32  // Framebuffer
+		ambient    uint32  // Ambient strength output texture [0,1] (Red channel)
+		uboSamples uint32  // Uniform Buffer Object pointing to the array of samples
+		shader     *Shader // SSAO pass shader
+
+		// SSAO blur pass
+		blur struct {
+			fbo    uint32
+			output uint32
+			shader *Shader
+		}
+	}
+
 	// Deferred lighting pass
 	lighting struct {
 		shader *Shader // Deferred lighting pass shaders
@@ -47,7 +76,7 @@ type WorldRenderer struct {
 
 	// Output pass
 	output struct {
-		fbo uint32 // Output framebuffer object.
+		fbo uint32 // Output framebuffer object, rendering to the output texture.
 		tex uint32 // Output texture, rendered to the back buffer at the end.
 		//depth uint32  // Output depth renderbuffer, use gbuffer.depth
 		shader *Shader // Shader used to copy output.tex to back buffer.
@@ -64,23 +93,31 @@ func (r *WorldRenderer) Init(w *world.World) (err error) {
 
 	r.depthmap.shader, err = NewShader(asset.WorldShaderShadowmapVert, asset.WorldShaderShadowmapFrag)
 	if err != nil {
-		return err
+		return errors.New("depthmap: " + err.Error())
 	}
 	r.gbuffer.shader, err = NewShader(asset.WorldShaderGeometryVert, asset.WorldShaderGeometryFrag)
 	if err != nil {
-		return err
+		return errors.New("gbuffer: " + err.Error())
+	}
+	r.ssao.shader, err = NewShader(asset.WorldShaderSSAOVert, asset.WorldShaderSSAOFrag)
+	if err != nil {
+		return errors.New("ssao: " + err.Error())
+	}
+	r.ssao.blur.shader, err = NewShader(asset.WorldShaderSSAOBlurVert, asset.WorldShaderSSAOBlurFrag)
+	if err != nil {
+		return errors.New("ssao_blur: " + err.Error())
 	}
 	r.lighting.shader, err = NewShader(asset.WorldShaderLightingVert, asset.WorldShaderLightingFrag)
 	if err != nil {
-		return err
+		return errors.New("lighting: " + err.Error())
 	}
 	r.water.shader, err = NewShader(asset.WorldShaderWaterVert, asset.WorldShaderWaterFrag)
 	if err != nil {
-		return err
+		return errors.New("water: " + err.Error())
 	}
 	r.output.shader, err = NewShader(asset.WorldShaderOutputVert, asset.WorldShaderOutputFrag)
 	if err != nil {
-		return err
+		return errors.New("output: " + err.Error())
 	}
 
 	asset.InitWorldTextureAtlas()
@@ -97,6 +134,23 @@ func (r *WorldRenderer) Init(w *world.World) (err error) {
 	gl.BindFragDataLocation(r.water.shader.Handle(), 0, gl.Str("outputColor\x00"))
 	gl.BindFragDataLocation(r.output.shader.Handle(), 0, gl.Str("outputColor\x00"))
 
+	// generate random mapping
+	{
+		data := make([]uint32, RandomSize[0]*RandomSize[1])
+		for i := range data {
+			data[i] = rand.Uint32()
+		}
+		gl.GenTextures(1, &r.texRand)
+		gl.BindTexture(gl.TEXTURE_2D, r.texRand)
+		gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA, int32(RandomSize[0]), int32(RandomSize[1]), 0, gl.RGBA, gl.UNSIGNED_BYTE, util.Ptr(data))
+		gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
+		gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
+		gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.REPEAT)
+		gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.REPEAT)
+	}
+	r.ssao.shader.SetUniformTextureHandle("rand", r.texRand)
+	r.ssao.shader.SetUniformVec2f("randSize", RandomSize.ToFloat32())
+
 	// generate the depthmap and depthmap FBO
 	gl.GenFramebuffers(1, &r.depthmap.fbo)
 	gl.GenTextures(1, &r.depthmap.tex)
@@ -126,6 +180,10 @@ func (r *WorldRenderer) Init(w *world.World) (err error) {
 	gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA32F, int32(io.DisplaySize[0]), int32(io.DisplaySize[1]), 0, gl.RGBA, gl.FLOAT, nil)
 	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
 	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_BORDER)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_BORDER)
+	borderColor = []float32{1, 1, 1, 1}
+	gl.TexParameterfv(gl.TEXTURE_2D, gl.TEXTURE_BORDER_COLOR, &borderColor[0])
 	gl.FramebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, r.gbuffer.pos, 0)
 	// normal
 	gl.GenTextures(1, &r.gbuffer.norm)
@@ -153,6 +211,48 @@ func (r *WorldRenderer) Init(w *world.World) (err error) {
 	r.lighting.shader.SetUniformTextureHandle("gPos", r.gbuffer.pos)
 	r.lighting.shader.SetUniformTextureHandle("gNorm", r.gbuffer.norm)
 	r.lighting.shader.SetUniformTextureHandle("gColor", r.gbuffer.color)
+	r.ssao.shader.SetUniformTextureHandle("gPos", r.gbuffer.pos)
+	r.ssao.shader.SetUniformTextureHandle("gNorm", r.gbuffer.norm)
+
+	// generate SSAO friends
+	gl.GenFramebuffers(1, &r.ssao.fbo)
+	gl.BindFramebuffer(gl.FRAMEBUFFER, r.ssao.fbo)
+	// ambient strength texture
+	gl.GenTextures(1, &r.ssao.ambient)
+	gl.BindTexture(gl.TEXTURE_2D, r.ssao.ambient)
+	gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RED, int32(io.DisplaySize[0]), int32(io.DisplaySize[1]), 0, gl.RED, gl.UNSIGNED_BYTE, nil)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
+	gl.FramebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, r.ssao.ambient, 0)
+	r.ssao.blur.shader.SetUniformTextureHandle("input", r.ssao.ambient)
+	// uniform buffer object for samples
+	ssaoSamples := make([]itype.Vec4f, SSAOSampleCount)
+	for i := range ssaoSamples {
+		sample := itype.Vec3d{rand.Float64()*2 - 1, rand.Float64()*2 - 1, rand.Float64() + 0.05}
+		sample = sample.Normalize().Multiply(rand.Float64()).Multiply(rand.Float64())
+		ssaoSamples[i] = itype.Vec4f{
+			float32(sample[0]),
+			float32(sample[1]),
+			float32(sample[2]),
+			0,
+		}
+	}
+	gl.GenBuffers(1, &r.ssao.uboSamples)
+	gl.BindBuffer(gl.UNIFORM_BUFFER, r.ssao.uboSamples)
+	gl.BufferData(gl.UNIFORM_BUFFER, int(unsafe.Sizeof(float32(0))*4*SSAOSampleCount), util.Ptr(ssaoSamples), gl.STATIC_DRAW)
+	// bind UBO (onto binding 0 for now)
+	gl.BindBufferBase(gl.UNIFORM_BUFFER, 0, r.ssao.uboSamples)
+	gl.UniformBlockBinding(r.ssao.shader.Handle(), gl.GetUniformBlockIndex(r.ssao.shader.Handle(), gl.Str("uboSamples\x00")), 0)
+	// SSAO blur pass
+	gl.GenFramebuffers(1, &r.ssao.blur.fbo)
+	gl.BindFramebuffer(gl.FRAMEBUFFER, r.ssao.blur.fbo)
+	gl.GenTextures(1, &r.ssao.blur.output)
+	gl.BindTexture(gl.TEXTURE_2D, r.ssao.blur.output)
+	gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RED, int32(io.DisplaySize[0]), int32(io.DisplaySize[1]), 0, gl.RED, gl.UNSIGNED_BYTE, nil)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
+	gl.FramebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, r.ssao.blur.output, 0)
+	r.lighting.shader.SetUniformTextureHandle("ssaoAmbient", r.ssao.blur.output)
 
 	// generate the output texture and friends
 	gl.GenFramebuffers(1, &r.output.fbo)
@@ -171,6 +271,7 @@ func (r *WorldRenderer) Init(w *world.World) (err error) {
 
 	gl.BindFramebuffer(gl.FRAMEBUFFER, 0)
 	r.lastDisplaySize = io.DisplaySize
+	r.startTime = time.Now()
 
 	initScreenQuad()
 
@@ -191,15 +292,19 @@ func (r *WorldRenderer) Render(world *world.World, view *View) {
 
 	// re-generate the G-buffers if the display size changed
 	if r.lastDisplaySize != io.DisplaySize {
-		gl.BindTexture(gl.TEXTURE_2D, r.gbuffer.pos)
+		gl.BindTexture(gl.TEXTURE_2D, r.gbuffer.pos) // G-Buffer, Position
+		gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA32F, int32(io.DisplaySize[0]), int32(io.DisplaySize[1]), 0, gl.RGBA, gl.FLOAT, nil)
+		gl.BindTexture(gl.TEXTURE_2D, r.gbuffer.norm) // G-Buffer, Normal
 		gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA16F, int32(io.DisplaySize[0]), int32(io.DisplaySize[1]), 0, gl.RGBA, gl.FLOAT, nil)
-		gl.BindTexture(gl.TEXTURE_2D, r.gbuffer.norm)
+		gl.BindTexture(gl.TEXTURE_2D, r.gbuffer.color) // G-Buffer, Albedo Color
-		gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA16F, int32(io.DisplaySize[0]), int32(io.DisplaySize[1]), 0, gl.RGBA, gl.FLOAT, nil)
-		gl.BindTexture(gl.TEXTURE_2D, r.gbuffer.color)
 		gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA, int32(io.DisplaySize[0]), int32(io.DisplaySize[1]), 0, gl.RGBA, gl.UNSIGNED_BYTE, nil)
-		gl.BindRenderbuffer(gl.RENDERBUFFER, r.gbuffer.depth)
+		gl.BindRenderbuffer(gl.RENDERBUFFER, r.gbuffer.depth) // G-Buffer, Depth (Renderbuffer)
 		gl.RenderbufferStorage(gl.RENDERBUFFER, gl.DEPTH_COMPONENT16, int32(io.DisplaySize[0]), int32(io.DisplaySize[1]))
-		gl.BindTexture(gl.TEXTURE_2D, r.output.tex)
+		gl.BindTexture(gl.TEXTURE_2D, r.ssao.ambient) // SSAO Output Ambient Strength
+		gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RED, int32(io.DisplaySize[0]), int32(io.DisplaySize[1]), 0, gl.RED, gl.UNSIGNED_BYTE, nil)
+		gl.BindTexture(gl.TEXTURE_2D, r.ssao.blur.output) // SSAO Blurred Output
+		gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RED, int32(io.DisplaySize[0]), int32(io.DisplaySize[1]), 0, gl.RED, gl.UNSIGNED_BYTE, nil)
+		gl.BindTexture(gl.TEXTURE_2D, r.output.tex) // Output Texture
 		gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA, int32(io.DisplaySize[0]), int32(io.DisplaySize[1]), 0, gl.RGBA, gl.UNSIGNED_BYTE, nil)
 		r.lastDisplaySize = io.DisplaySize
 	}
@@ -250,7 +355,29 @@ func (r *WorldRenderer) Render(world *world.World, view *View) {
 
 	world.Render()
 
-	// 3. Render the actual output with deferred lighting
+	// 3/1. SSAO pass
+	gl.BindFramebuffer(gl.FRAMEBUFFER, r.ssao.fbo)
+	gl.ClearColor(1, 1, 1, 1)
+	gl.Clear(gl.COLOR_BUFFER_BIT)
+
+	r.ssao.shader.UseProgram()
+	r.ssao.shader.BindTextures()
+	r.ssao.shader.SetUniformMat4("view", view.View())
+	r.ssao.shader.SetUniformMat4("projection", view.Perspective())
+	r.ssao.shader.SetUniformVec3f("viewPos", view.EyePos)
+	r.ssao.shader.SetUniformFloat("time", float32(time.Since(r.startTime).Seconds()))
+
+	DrawScreenQuad()
+
+	// 3/2. SSAO blur pass (TODO)
+	gl.BindFramebuffer(gl.FRAMEBUFFER, r.ssao.blur.fbo)
+	r.ssao.blur.shader.UseProgram()
+	r.ssao.blur.shader.BindTextures()
+	r.ssao.blur.shader.SetUniformVec2f("screenSize", r.lastDisplaySize.ToFloat32())
+
+	DrawScreenQuad()
+
+	// 4. Render the actual output with deferred lighting
 	gl.BindFramebuffer(gl.FRAMEBUFFER, r.output.fbo)
 	gl.ClearColor(io.ClearColor[0], io.ClearColor[1], io.ClearColor[2], io.ClearColor[3])
 	gl.Clear(gl.COLOR_BUFFER_BIT)
@@ -264,7 +391,7 @@ func (r *WorldRenderer) Render(world *world.World, view *View) {
 
 	DrawScreenQuad()
 
-	// 4. Render water
+	// 5. Render water
 	gl.Enable(gl.DEPTH_TEST)
 	gl.DepthFunc(gl.LESS)
 	gl.Enable(gl.CULL_FACE)