diff --git a/internal/asset/shader.go b/internal/asset/shader.go index d457933..eb1c070 100644 --- a/internal/asset/shader.go +++ b/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 diff --git a/internal/asset/shader/world/geometry.frag b/internal/asset/shader/world/geometry.frag index 4388bdf..f22028d 100644 --- a/internal/asset/shader/world/geometry.frag +++ b/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); } diff --git a/internal/asset/shader/world/geometry.vert b/internal/asset/shader/world/geometry.vert index c859b33..877d7e5 100644 --- a/internal/asset/shader/world/geometry.vert +++ b/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; } diff --git a/internal/asset/shader/world/lighting.frag b/internal/asset/shader/world/lighting.frag index c25a37e..a80a95f 100644 --- a/internal/asset/shader/world/lighting.frag +++ b/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(); diff --git a/internal/asset/shader/world/ssao.frag b/internal/asset/shader/world/ssao.frag new file mode 100644 index 0000000..fac6f9a --- /dev/null +++ b/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); +} diff --git a/internal/asset/shader/world/ssao.vert b/internal/asset/shader/world/ssao.vert new file mode 100644 index 0000000..fd8b422 --- /dev/null +++ b/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; +} + diff --git a/internal/asset/shader/world/ssao_blur.frag b/internal/asset/shader/world/ssao_blur.frag new file mode 100644 index 0000000..5f8de82 --- /dev/null +++ b/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; +} + diff --git a/internal/asset/shader/world/ssao_blur.vert b/internal/asset/shader/world/ssao_blur.vert new file mode 100644 index 0000000..fd8b422 --- /dev/null +++ b/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; +} + diff --git a/internal/render/render_world.go b/internal/render/render_world.go index 003ebc2..f5dc3af 100644 --- a/internal/render/render_world.go +++ b/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.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.BindTexture(gl.TEXTURE_2D, r.gbuffer.color) // G-Buffer, Albedo 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)