src/shader.cpp

   1 #include "shader.hpp"
   2
   3 #include "init.hpp"
   4
   5 #include <algorithm>
   6 #include <iostream>
   7 #include <memory>
   8 #include <ostream>
   9 #include <stdexcept>
  10 #include <string>
  11
  12
  13 namespace {
  14
  15 void gl_error(std::string msg) {
  16         const GLubyte *errBegin = gluErrorString(glGetError());
  17         if (errBegin && *errBegin != '\0') {
  18                 const GLubyte *errEnd = errBegin;
  19                 while (*errEnd != '\0') {
  20                         ++errEnd;
  21                 }
  22                 msg += ": ";
  23                 msg.append(errBegin, errEnd);
  24         }
  25         throw std::runtime_error(msg);
  26 }
  27
  28 }
  29
  30 namespace blank {
  31
  32 Shader::Shader(GLenum type)
  33 : handle(glCreateShader(type)) {
  34         if (handle == 0) {
  35                 gl_error("glCreateShader");
  36         }
  37 }
  38
  39 Shader::~Shader() {
  40         if (handle != 0) {
  41                 glDeleteShader(handle);
  42         }
  43 }
  44
  45 Shader::Shader(Shader &&other)
  46 : handle(other.handle) {
  47         other.handle = 0;
  48 }
  49
  50 Shader &Shader::operator =(Shader &&other) {
  51         std::swap(handle, other.handle);
  52         return *this;
  53 }
  54
  55
  56 void Shader::Source(const GLchar *src) {
  57         const GLchar* src_arr[] = { src };
  58         glShaderSource(handle, 1, src_arr, nullptr);
  59 }
  60
  61 void Shader::Compile() {
  62         glCompileShader(handle);
  63 }
  64
  65 bool Shader::Compiled() const {
  66         GLint compiled = GL_FALSE;
  67         glGetShaderiv(handle, GL_COMPILE_STATUS, &compiled);
  68         return compiled == GL_TRUE;
  69 }
  70
  71 void Shader::Log(std::ostream &out) const {
  72         int log_len = 0, max_len = 0;
  73         glGetShaderiv(handle, GL_INFO_LOG_LENGTH, &max_len);
  74         std::unique_ptr<char[]> log(new char[max_len]);
  75         glGetShaderInfoLog(handle, max_len, &log_len, log.get());
  76         out.write(log.get(), log_len);
  77 }
  78
  79
  80 void Shader::AttachToProgram(GLuint id) const {
  81         glAttachShader(id, handle);
  82 }
  83
  84
  85 Program::Program()
  86 : handle(glCreateProgram()) {
  87         if (handle == 0) {
  88                 gl_error("glCreateProgram");
  89         }
  90 }
  91
  92 Program::~Program() {
  93         if (handle != 0) {
  94                 glDeleteProgram(handle);
  95         }
  96 }
  97
  98
  99 const Shader &Program::LoadShader(GLenum type, const GLchar *src) {
 100         shaders.emplace_back(type);
 101         Shader &shader = shaders.back();
 102         shader.Source(src);
 103         shader.Compile();
 104         if (!shader.Compiled()) {
 105                 shader.Log(std::cerr);
 106                 throw std::runtime_error("compile shader");
 107         }
 108         Attach(shader);
 109         return shader;
 110 }
 111
 112 void Program::Attach(Shader &shader) {
 113         shader.AttachToProgram(handle);
 114 }
 115
 116 void Program::Link() {
 117         glLinkProgram(handle);
 118 }
 119
 120 bool Program::Linked() const {
 121         GLint linked = GL_FALSE;
 122         glGetProgramiv(handle, GL_LINK_STATUS, &linked);
 123         return linked == GL_TRUE;
 124 }
 125
 126 void Program::Log(std::ostream &out) const {
 127         int log_len = 0, max_len = 0;
 128         glGetProgramiv(handle, GL_INFO_LOG_LENGTH, &max_len);
 129         std::unique_ptr<char[]> log(new char[max_len]);
 130         glGetProgramInfoLog(handle, max_len, &log_len, log.get());
 131         out.write(log.get(), log_len);
 132 }
 133
 134
 135 GLint Program::UniformLocation(const GLchar *name) const {
 136         return glGetUniformLocation(handle, name);
 137 }
 138
 139
 140 DirectionalLighting::DirectionalLighting()
 141 : program()
 142 , light_direction(1.0f, 3.0f, 2.0f)
 143 , light_color(0.9f, 0.9f, 0.9f)
 144 , vp(1.0f)
 145 , m_handle(0)
 146 , mvp_handle(0)
 147 , light_direction_handle(0)
 148 , light_color_handle(0) {
 149         program.LoadShader(
 150                 GL_VERTEX_SHADER,
 151                 "#version 330 core\n"
 152                 "layout(location = 0) in vec3 vtx_position;\n"
 153                 "layout(location = 1) in vec3 vtx_color;\n"
 154                 "layout(location = 2) in vec3 vtx_normal;\n"
 155                 "uniform mat4 M;\n"
 156                 "uniform mat4 MVP;\n"
 157                 "out vec3 frag_color;\n"
 158                 "out vec3 normal;\n"
 159                 "void main() {\n"
 160                         "gl_Position = MVP * vec4(vtx_position, 1);\n"
 161                         "normal = (M * vec4(vtx_normal, 0)).xyz;\n"
 162                         "frag_color = vtx_color;\n"
 163                 "}\n"
 164         );
 165         program.LoadShader(
 166                 GL_FRAGMENT_SHADER,
 167                 "#version 330 core\n"
 168                 "in vec3 frag_color;\n"
 169                 "in vec3 normal;\n"
 170                 "uniform vec3 light_direction;\n"
 171                 "uniform vec3 light_color;\n"
 172                 "out vec3 color;\n"
 173                 "void main() {\n"
 174                         "vec3 ambient = vec3(0.1, 0.1, 0.1) * frag_color;\n"
 175                         "vec3 n = normalize(normal);\n"
 176                         "vec3 l = normalize(light_direction);\n"
 177                         "float cos_theta = clamp(dot(n, l), 0, 1);\n"
 178                         "color = ambient + frag_color * light_color * cos_theta;\n"
 179                 "}\n"
 180         );
 181         program.Link();
 182         if (!program.Linked()) {
 183                 program.Log(std::cerr);
 184                 throw std::runtime_error("link program");
 185         }
 186
 187         m_handle = program.UniformLocation("M");
 188         mvp_handle = program.UniformLocation("MVP");
 189         light_direction_handle = program.UniformLocation("light_direction");
 190         light_color_handle = program.UniformLocation("light_color");
 191 }
 192
 193
 194 void DirectionalLighting::Activate() {
 195         GLContext::EnableDepthTest();
 196         GLContext::EnableBackfaceCulling();
 197         program.Use();
 198
 199         glUniform3f(light_direction_handle, light_direction.x, light_direction.y, light_direction.z);
 200         glUniform3f(light_color_handle, light_color.x, light_color.y, light_color.z);
 201 }
 202
 203 void DirectionalLighting::SetM(const glm::mat4 &m) {
 204         glm::mat4 mvp(vp * m);
 205         glUniformMatrix4fv(m_handle, 1, GL_FALSE, &m[0][0]);
 206         glUniformMatrix4fv(mvp_handle, 1, GL_FALSE, &mvp[0][0]);
 207 }
 208
 209 void DirectionalLighting::SetLightDirection(const glm::vec3 &dir) {
 210         light_direction = -dir;
 211         glUniform3f(light_direction_handle, light_direction.x, light_direction.y, light_direction.z);
 212 }
 213
 214 void DirectionalLighting::SetProjection(const glm::mat4 &p) {
 215         projection = p;
 216         vp = p * view;
 217 }
 218
 219 void DirectionalLighting::SetView(const glm::mat4 &v) {
 220         view = v;
 221         vp = projection * v;
 222 }
 223
 224 void DirectionalLighting::SetVP(const glm::mat4 &v, const glm::mat4 &p) {
 225         projection = p;
 226         view = v;
 227         vp = p * v;
 228 }
 229
 230 void DirectionalLighting::SetMVP(const glm::mat4 &m, const glm::mat4 &v, const glm::mat4 &p) {
 231         SetVP(v, p);
 232         SetM(m);
 233 }
 234
 235 }