Purpose of the Sample:
Demonstrates how to make a toon shader using a stencil buffer for the silhouette.
CGame.h
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#ifndef __CGAME__ #define __CGAME__ #include <glad/glad.h> #include "shader_s.h" class Model; class Mesh; class CGame { public: CGame() {}; void Initialize(unsigned int screenWidth, unsigned int screenHeight); void Shutdown(); void Render(); void OnResize(int screenWidth, int screenHeight); private: void SetupGPUProgram(); void SetupModel(); Shader* m_pShaderPass0; Shader* m_pShaderPass1; Shader* m_pShaderPass2; Model* m_pManModel; Model* m_pQuad; GLuint m_ColorTextureId; GLuint m_IntermediateFBOId; GLuint m_TekkaTexture; GLuint m_RampTexture; unsigned int m_Width; unsigned int m_Height; }; #endif |
CGame.cpp
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#include "CGame.h" #define STB_IMAGE_IMPLEMENTATION #include "stb_image/stb_image.h" #include "Model.h" #include "Mesh.h" #include "glm/mat4x4.hpp" #include "glm/vec3.hpp" #include "glm/glm.hpp" #include "glm/gtc/matrix_transform.hpp" #include "glm/gtc/type_ptr.hpp" #include void CGame::Initialize(unsigned int screenWidth, unsigned int screenHeight) { m_Width = screenWidth; m_Height = screenHeight; SetupGPUProgram(); SetupModel(); glEnable(GL_DEPTH_TEST); glDepthFunc(GL_LEQUAL); glEnable(GL_MULTISAMPLE); glEnable(GL_STENCIL_TEST); GLuint depthStencilId; glGenFramebuffers(1, &m_IntermediateFBOId); glBindFramebuffer(GL_FRAMEBUFFER, m_IntermediateFBOId); glGenTextures(1, &m_ColorTextureId); glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, m_ColorTextureId); glTexImage2DMultisample(GL_TEXTURE_2D_MULTISAMPLE, 4, GL_RGB8, m_Width, m_Height, GL_TRUE); glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D_MULTISAMPLE, m_ColorTextureId, 0); glGenRenderbuffers(1, &depthStencilId); glBindRenderbuffer(GL_RENDERBUFFER, depthStencilId); glRenderbufferStorageMultisample(GL_RENDERBUFFER, 4, GL_DEPTH24_STENCIL8, screenWidth, screenHeight); glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, depthStencilId); if (glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE) { // Great! } glBindFramebuffer(GL_FRAMEBUFFER, 0); } void CGame::Shutdown() { } void CGame::OnResize(int width, int height) { m_Width = width; m_Height = height; glViewport(0, 0, m_Width, m_Height); glScissor(0, 0, m_Width, m_Height); } void CGame::Render() { static auto startTime = std::chrono::high_resolution_clock::now(); auto currentTime = std::chrono::high_resolution_clock::now(); float time = std::chrono::duration<float, std::chrono::seconds::period>(currentTime - startTime).count(); glEnable(GL_MULTISAMPLE); glBindFramebuffer(GL_FRAMEBUFFER, m_IntermediateFBOId); glEnable(GL_STENCIL_TEST); glClearColor(0.2f, 0.2f, 0.2f, 1.0f); glClearDepth(1.0f); glClearStencil(0); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT); // Draw the Filled Man glEnable(GL_CULL_FACE); glFrontFace(GL_CCW); glCullFace(GL_BACK); // Fill the stencil buffer with 1 anywhere our tekka model is drawn. glStencilFunc(GL_ALWAYS, 3, 0xFF); glStencilOp(GL_REPLACE, GL_REPLACE, GL_REPLACE); glm::mat4 model = glm::rotate(glm::mat4(1.0f), time * glm::radians(60.0f), glm::vec3(0.0f, 1.0f, 0.0f)); glm::mat4 view; glm::vec3 eyePos = glm::vec3(0.0f, -1.0f, -2.5f); view = glm::translate(glm::mat4(1.0f), eyePos); glm::mat4 projection; projection = glm::perspective(glm::radians(60.0f), m_Width / static_cast(m_Height), 0.03f, 100.0f); glm::mat4 mvp = projection * view * model; glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, m_TekkaTexture); glActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_2D, m_RampTexture); m_pShaderPass0->use(); // This must be done to assign the texture samplers to a texture unit. m_pShaderPass0->setInt("mainTexture", 0); m_pShaderPass0->setInt("rampTexture", 1); m_pShaderPass0->setMatrix4x4("modelMatrix", glm::value_ptr(model)); m_pShaderPass0->setMatrix4x4("viewMatrix", glm::value_ptr(view)); m_pShaderPass0->setMatrix4x4("projectionMatrix", glm::value_ptr(projection)); m_pShaderPass0->setMatrix4x4("mvpMatrix", glm::value_ptr(mvp)); m_pShaderPass0->setVector3("eyePos", glm::value_ptr(eyePos)); m_pShaderPass0->setFloat("time", time); m_pManModel->meshes[0].Draw(*m_pShaderPass0); // Draw Silhouette glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, 0); glActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_2D, 0); glCullFace(GL_FRONT); // When we drew tekka in the first pass at the normal size and with his texture, // we filled the stencil buffer with the value 3 anywhere he was drawn. The rest of // the stencil buffer was cleared to 0. // We don't want the Silhouette to be drawn over tekka. We only want the Silhouette to be // drawn around tekka. Remember, everything at this point in the stencil buffer is 0 // except for where tekka was drawn which is 3. Therefore to make the outline, // we will AND 3 with 1 and if it comes back as 1, we will not keep the contents of the buffer. glStencilFunc(GL_NOTEQUAL, 1, 0x01); float silhouetteThickness = 0.02f; glm::vec3 silhouetteColor = glm::vec3(1, 0, 0); m_pShaderPass1->use(); m_pShaderPass1->setMatrix4x4("modelMatrix", glm::value_ptr(model)); m_pShaderPass1->setMatrix4x4("viewMatrix", glm::value_ptr(view)); m_pShaderPass1->setMatrix4x4("projectionMatrix", glm::value_ptr(projection)); m_pShaderPass1->setMatrix4x4("mvpMatrix", glm::value_ptr(mvp)); m_pShaderPass1->setVector3("eyePos", glm::value_ptr(eyePos)); m_pShaderPass1->setFloat("time", time); m_pShaderPass1->setFloat("silhouetteThickness", silhouetteThickness); m_pShaderPass1->setVector3("silhouetteColor", glm::value_ptr(silhouetteColor)); m_pManModel->meshes[0].Draw(*m_pShaderPass1); glDisable(GL_STENCIL_TEST); // Draw a Floor quad glCullFace(GL_BACK); silhouetteColor = glm::vec3(0.4f, 0.4f, 0.4f); model = glm::translate(glm::mat4(1.0f), glm::vec3(0.0f, -0.2f, 0.0f)); model = glm::scale(model, glm::vec3(5.0f, 5.0f, 5.0f)); mvp = projection * view * model; m_pShaderPass2->use(); m_pShaderPass2->setMatrix4x4("modelMatrix", glm::value_ptr(model)); m_pShaderPass2->setMatrix4x4("viewMatrix", glm::value_ptr(view)); m_pShaderPass2->setMatrix4x4("projectionMatrix", glm::value_ptr(projection)); m_pShaderPass2->setMatrix4x4("mvpMatrix", glm::value_ptr(mvp)); m_pShaderPass2->setVector3("eyePos", glm::value_ptr(eyePos)); m_pShaderPass2->setFloat("time", time); m_pShaderPass2->setFloat("silhouetteThickness", silhouetteThickness); m_pShaderPass2->setVector3("silhouetteColor", glm::value_ptr(silhouetteColor)); m_pQuad->meshes[0].Draw(*m_pShaderPass2); // Blit intermediate FBO to backbuffer FBO glDisable(GL_STENCIL_TEST); glBindFramebuffer(GL_FRAMEBUFFER, 0); glBindFramebuffer(GL_READ_FRAMEBUFFER, m_IntermediateFBOId); glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0); glBlitFramebuffer(0, 0, m_Width, m_Height, 0, 0, m_Width, m_Height, GL_COLOR_BUFFER_BIT, GL_NEAREST); } void CGame::SetupModel() { m_pManModel = new Model(); m_pManModel->Load("tekka.obj"); m_pQuad = new Model(); m_pQuad->Load("quad.obj"); int width, height, nrChannels; unsigned char *data = stbi_load("tekka.png", &width, &height, &nrChannels, 0); glGenTextures(1, &m_TekkaTexture); glBindTexture(GL_TEXTURE_2D, m_TekkaTexture); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data); glGenerateMipmap(GL_TEXTURE_2D); unsigned char *data2 = stbi_load("ramp3.png", &width, &height, &nrChannels, 0); glGenTextures(1, &m_RampTexture); glBindTexture(GL_TEXTURE_2D, m_RampTexture); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data2); glGenerateMipmap(GL_TEXTURE_2D); } void CGame::SetupGPUProgram() { m_pShaderPass0 = new Shader("vertexPass0.glsl", "fragmentPass0.glsl"); m_pShaderPass1 = new Shader("vertexPass1.glsl", "fragmentPass1.glsl"); m_pShaderPass2 = new Shader("vertexPass1.glsl", "fragmentPass2.glsl"); } |
vertexPass0.glsl
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#version 330 core layout (location = 0) in vec3 position; layout (location = 1) in vec3 normal; layout (location = 2) in vec2 uv; uniform mat4 modelMatrix; uniform mat4 viewMatrix; uniform mat4 projectionMatrix; uniform mat4 mvpMatrix; uniform vec3 eyePos; uniform float time; out vec3 fsNormal; out vec2 fsUV; void main() { vec4 pos = mvpMatrix * vec4(position.xyz, 1); fsNormal = vec3(modelMatrix * viewMatrix * vec4(normal, 0)).xyz; fsUV = uv; gl_Position = pos; } |
fragmentPass0.glsl
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#version 330 core out vec4 FragColor; in vec3 fsNormal; in vec2 fsUV; uniform vec3 eyePos; uniform sampler2D mainTexture; uniform sampler2D rampTexture; void main() { vec3 lightDir = normalize(vec3(0, 0, 1)); vec3 normal = normalize(fsNormal); float nDotl = clamp(dot(normal, lightDir), 0, 1); float ramp = texture(rampTexture, vec2(nDotl, 0.5)).r; vec3 albedo = texture(mainTexture, fsUV).rgb; vec3 diffuse = albedo * pow(ramp, 1.3); FragColor = vec4(diffuse, 1.0f); } |
vertexPass1.glsl
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#version 330 core layout (location = 0) in vec3 position; layout (location = 1) in vec3 normal; uniform mat4 modelMatrix; uniform mat4 viewMatrix; uniform mat4 projectionMatrix; uniform mat4 mvpMatrix; uniform float time; uniform float silhouetteThickness; uniform vec3 silhouetteColor; out vec3 fsSilhouetteColor; out float fsTime; void main() { vec4 pos = mvpMatrix * vec4(position.xyz + (normal * silhouetteThickness), 1); fsSilhouetteColor = silhouetteColor; fsTime = time; gl_Position = pos; } |
fragmentPass1.glsl
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#version 330 core out vec4 FragColor; in vec3 fsSilhouetteColor; in float fsTime; void main() { float t = sin(fsTime * 5.0) * 0.5 + 0.5; vec3 baseColor = vec3(0.5, 0.1, 0.0); vec3 color = mix(baseColor, fsSilhouetteColor, t); FragColor = vec4(color, 1.0f); } |
fragmentPass2.glsl
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#version 330 core out vec4 FragColor; in vec3 fsSilhouetteColor; in float fsTime; void main() { FragColor = vec4(fsSilhouetteColor, 1.0f); } |