理解OpenGLSuperbible7-GSLayers

2019-11-09 16:46:22

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#include "GLContext.h"#include <GL/gl.h>#include "common/shader.hpp"#include "common/vmath.h"#include "common/object.h"#include <string>static void PRint_shader_log(GLuint shader){ std::string str; GLint len; glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &len); str.resize(len); glGetShaderInfoLog(shader, len, NULL, &str[0]);#ifdef _WIN32 OutputDebugStringA(str.c_str());#endif}class GSLayeredApp : public GLapplication{public: GSLayeredApp() : program_gslayers(0), program_showlayers(0), mode(0) { } void init() { static const char title[] = "OpenGL SuperBible - Layered Rendering"; GLApplication::init(); memcpy(mInfo.title, title, sizeof(title)); } void startup(void) { glGenVertexArrays(1, &vao); glBindVertexArray(vao); load_shaders(); obj.load("media/objects/torus.sbm"); glGenBuffers(1, &transform_ubo); glBindBuffer(GL_UNIFORM_BUFFER, transform_ubo); glBufferData(GL_UNIFORM_BUFFER, 17 * sizeof(vmath::mat4), NULL, GL_DYNAMIC_DRAW); glGenTextures(1, &array_texture); glBindTexture(GL_TEXTURE_2D_ARRAY, array_texture); glTexStorage3D(GL_TEXTURE_2D_ARRAY, 1, GL_RGBA8, 256, 256, 16); glGenTextures(1, &array_depth); glBindTexture(GL_TEXTURE_2D_ARRAY, array_depth); glTexStorage3D(GL_TEXTURE_2D_ARRAY, 1, GL_DEPTH_COMPONENT32, 256, 256, 16); glGenFramebuffers(1, &layered_fbo); glBindFramebuffer(GL_FRAMEBUFFER, layered_fbo); glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, array_texture, 0); glFramebufferTexture(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, array_depth, 0); } void shutdown(void) { glDeleteProgram(program_showlayers); glDeleteProgram(program_gslayers); glDeleteVertexArrays(1, &vao); } void render(double t) { static const GLfloat black[] = { 0.0f, 0.0f, 0.0f, 1.0f }; static const GLfloat gray[] = { 0.1f, 0.1f, 0.1f, 1.0f }; static const GLfloat one = 1.0f; vmath::mat4 mv_matrix = vmath::translate(0.0f, 0.0f, -4.0f) * vmath::rotate((float)t * 5.0f, 0.0f, 0.0f, 1.0f) * vmath::rotate((float)t * 30.0f, 1.0f, 0.0f, 0.0f); vmath::mat4 proj_matrix = vmath::perspective(50.0f, (float)mInfo.windowWidth / (float)mInfo.windowHeight, 0.1f, 1000.0f); vmath::mat4 mvp = proj_matrix * mv_matrix; struct TRANSFORM_BUFFER { vmath::mat4 proj_matrix; vmath::mat4 mv_matrix[16]; }; glBindBufferBase(GL_UNIFORM_BUFFER, 0, transform_ubo); TRANSFORM_BUFFER * buffer = (TRANSFORM_BUFFER *)glMapBufferRange(GL_UNIFORM_BUFFER, 0, sizeof(TRANSFORM_BUFFER), GL_MAP_WRITE_BIT | GL_MAP_INVALIDATE_BUFFER_BIT); buffer->proj_matrix = vmath::perspective(50.0f, 1.0f, 0.1f, 1000.0f); // proj_matrix; int i; for (i = 0; i < 16; i++) { float fi = (float)(i + 12) / 16.0f; buffer->mv_matrix[i] = vmath::translate(0.0f, 0.0f, -4.0f) * vmath::rotate((float)t * 25.0f * fi, 0.0f, 0.0f, 1.0f) * vmath::rotate((float)t * 30.0f * fi, 1.0f, 0.0f, 0.0f); } glUnmapBuffer(GL_UNIFORM_BUFFER); static const GLenum ca0 = GL_COLOR_ATTACHMENT0; glBindFramebuffer(GL_FRAMEBUFFER, layered_fbo); glDrawBuffers(1, &ca0); glViewport(0, 0, 256, 256); glClearBufferfv(GL_COLOR, 0, black); glClearBufferfv(GL_DEPTH, 0, &one); glEnable(GL_DEPTH_TEST); glDepthFunc(GL_LEQUAL); glUseProgram(program_gslayers); obj.render(); glBindFramebuffer(GL_FRAMEBUFFER, 0); glDrawBuffer(GL_BACK); glUseProgram(program_showlayers); glViewport(0, 0, mInfo.windowWidth, mInfo.windowHeight); glClearBufferfv(GL_COLOR, 0, gray); glBindTexture(GL_TEXTURE_2D_ARRAY, array_texture); glDisable(GL_DEPTH_TEST); glBindVertexArray(vao); glDrawArraysInstanced(GL_TRIANGLE_FAN, 0, 4, 16); glBindTexture(GL_TEXTURE_2D_ARRAY, 0); } void onKey(int key, int action) { if (!action) return; switch (key) { case '1': case '2': mode = key - '1'; break; case 'R': load_shaders(); break; case 'M': mode = (mode + 1) % 2; break; } } void load_shaders() { GLuint vs; GLuint gs; GLuint fs; if (program_showlayers) glDeleteProgram(program_showlayers); program_showlayers = glCreateProgram(); vs = load("media/shaders/gslayers/showlayers.vs.glsl", GL_VERTEX_SHADER); fs = load("media/shaders/gslayers/showlayers.fs.glsl", GL_FRAGMENT_SHADER); glAttachShader(program_showlayers, vs); glAttachShader(program_showlayers, fs); glLinkProgram(program_showlayers); glDeleteShader(vs); glDeleteShader(fs); vs = load("media/shaders/gslayers/gslayers.vs.glsl", GL_VERTEX_SHADER); gs = load("media/shaders/gslayers/gslayers.gs.glsl", GL_GEOMETRY_SHADER); fs = load("media/shaders/gslayers/gslayers.fs.glsl", GL_FRAGMENT_SHADER); if (program_gslayers) glDeleteProgram(program_gslayers); program_gslayers = glCreateProgram(); glAttachShader(program_gslayers, vs); glAttachShader(program_gslayers, gs); glAttachShader(program_gslayers, fs); glLinkProgram(program_gslayers); glDeleteShader(vs); glDeleteShader(gs); glDeleteShader(fs); }private: GLuint program_gslayers; GLuint program_showlayers; GLuint vao; int mode; GLuint transform_ubo; GLuint layered_fbo; GLuint array_texture; GLuint array_depth; Object obj;};DECLARE_MAIN(GSLayeredApp);