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 , mv_handle(0)
 147 , mvp_handle(0)
 148 , light_direction_handle(0)
 149 , light_color_handle(0)
 150 , fog_density_handle(0) {
 151         program.LoadShader(
 152                 GL_VERTEX_SHADER,
 153                 "#version 330 core\n"
 154                 "layout(location = 0) in vec3 vtx_position;\n"
 155                 "layout(location = 1) in vec3 vtx_color;\n"
 156                 "layout(location = 2) in vec3 vtx_normal;\n"
 157                 "uniform mat4 M;\n"
 158                 "uniform mat4 MV;\n"
 159                 "uniform mat4 MVP;\n"
 160                 "out vec3 frag_color;\n"
 161                 "out vec3 vtx_viewspace;\n"
 162                 "out vec3 normal;\n"
 163                 "void main() {\n"
 164                         "gl_Position = MVP * vec4(vtx_position, 1);\n"
 165                         "vtx_viewspace = (MV * vec4(vtx_position, 1)).xyz;\n"
 166                         "normal = (M * vec4(vtx_normal, 0)).xyz;\n"
 167                         "frag_color = vtx_color;\n"
 168                 "}\n"
 169         );
 170         program.LoadShader(
 171                 GL_FRAGMENT_SHADER,
 172                 "#version 330 core\n"
 173                 "in vec3 frag_color;\n"
 174                 "in vec3 vtx_viewspace;\n"
 175                 "in vec3 normal;\n"
 176                 "uniform vec3 light_direction;\n"
 177                 "uniform vec3 light_color;\n"
 178                 "uniform float fog_density;\n"
 179                 "out vec3 color;\n"
 180                 "void main() {\n"
 181                         "vec3 ambient = vec3(0.1, 0.1, 0.1) * frag_color;\n"
 182                         // this should be the same as the clear color, otherwise looks really weird
 183                         "vec3 fog_color = vec3(0, 0, 0);\n"
 184                         "float e = 2.718281828;\n"
 185                         "vec3 n = normalize(normal);\n"
 186                         "vec3 l = normalize(light_direction);\n"
 187                         "float cos_theta = clamp(dot(n, l), 0, 1);\n"
 188                         "vec3 reflect_color = ambient + frag_color * light_color * cos_theta;\n"
 189                         "float value = pow(e, -pow(fog_density * length(vtx_viewspace), 5));"
 190                         "color = mix(fog_color, reflect_color, value);\n"
 191                 "}\n"
 192         );
 193         program.Link();
 194         if (!program.Linked()) {
 195                 program.Log(std::cerr);
 196                 throw std::runtime_error("link program");
 197         }
 198
 199         m_handle = program.UniformLocation("M");
 200         mv_handle = program.UniformLocation("MV");
 201         mvp_handle = program.UniformLocation("MVP");
 202         light_direction_handle = program.UniformLocation("light_direction");
 203         light_color_handle = program.UniformLocation("light_color");
 204         fog_density_handle = program.UniformLocation("fog_density");
 205 }
 206
 207
 208 void DirectionalLighting::Activate() {
 209         GLContext::EnableDepthTest();
 210         GLContext::EnableBackfaceCulling();
 211         program.Use();
 212
 213         glUniform3f(light_direction_handle, light_direction.x, light_direction.y, light_direction.z);
 214         glUniform3f(light_color_handle, light_color.x, light_color.y, light_color.z);
 215 }
 216
 217 void DirectionalLighting::SetM(const glm::mat4 &m) {
 218         glm::mat4 mv(view * m);
 219         glm::mat4 mvp(vp * m);
 220         glUniformMatrix4fv(m_handle, 1, GL_FALSE, &m[0][0]);
 221         glUniformMatrix4fv(mv_handle, 1, GL_FALSE, &mv[0][0]);
 222         glUniformMatrix4fv(mvp_handle, 1, GL_FALSE, &mvp[0][0]);
 223 }
 224
 225 void DirectionalLighting::SetLightDirection(const glm::vec3 &dir) {
 226         light_direction = -dir;
 227         glUniform3f(light_direction_handle, light_direction.x, light_direction.y, light_direction.z);
 228 }
 229
 230 void DirectionalLighting::SetFogDensity(float f) {
 231         fog_density = f;
 232         glUniform1f(fog_density_handle, fog_density);
 233 }
 234
 235 void DirectionalLighting::SetProjection(const glm::mat4 &p) {
 236         projection = p;
 237         vp = p * view;
 238 }
 239
 240 void DirectionalLighting::SetView(const glm::mat4 &v) {
 241         view = v;
 242         vp = projection * v;
 243 }
 244
 245 void DirectionalLighting::SetVP(const glm::mat4 &v, const glm::mat4 &p) {
 246         projection = p;
 247         view = v;
 248         vp = p * v;
 249 }
 250
 251 void DirectionalLighting::SetMVP(const glm::mat4 &m, const glm::mat4 &v, const glm::mat4 &p) {
 252         SetVP(v, p);
 253         SetM(m);
 254 }
 255
 256 }