src/engine/render.c

   1 #include "render.h"
   2
   3 #include <stdbool.h>
   4 #include <GL/glut.h>
   5
   6 #include "geometry.h"
   7 #include "performance.h"
   8
   9 #define SCENE_DEBUG_ 0
  10 #define RENDER_DEBUG_ 1
  11
  12 float viewportAspectRatio = 1.0f;
  13 const Scene* cameraAnchor;
  14
  15 static const float AXIS_RADIUS = 5.0f;
  16
  17 static void renderScene(const Scene*, const Transform baseTransform);
  18 static void setupCamera();
  19 static void moveCameraTo(const Scene* scene);
  20 static void drawAxes();
  21 static void drawSolid(const Solid* solid);
  22
  23
  24
  25 void initRender() {
  26         glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
  27
  28         GLfloat light0_ambient[] = {0.1f, 0.1f, 0.1f, 1.0f};
  29         GLfloat light0_diffuse[] = {1.0f, 1.0f, 1.0f, 1.0f};
  30         GLfloat light0_specular[] = {0.96f, 0.98f, 1.0f, 1.0f};
  31         GLfloat light0_position[] = {5.0f, 10.0f, 5.0f, 0.0f}; // (w == 0.0f) == directional
  32
  33         glLightfv(GL_LIGHT0, GL_AMBIENT, light0_ambient);
  34         glLightfv(GL_LIGHT0, GL_DIFFUSE, light0_diffuse);
  35         glLightfv(GL_LIGHT0, GL_SPECULAR, light0_specular);
  36         glLightfv(GL_LIGHT0, GL_POSITION, light0_position);
  37
  38         glLightf(GL_LIGHT0, GL_CONSTANT_ATTENUATION, 1.0f);
  39         glLightf(GL_LIGHT0, GL_LINEAR_ATTENUATION, 0.05f);
  40         glLightf(GL_LIGHT0, GL_QUADRATIC_ATTENUATION, 0.005f);
  41
  42         glShadeModel(GL_FLAT);
  43 }
  44
  45 void renderFrame() {
  46         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  47
  48         glEnable(GL_NORMALIZE);
  49         glEnable(GL_CULL_FACE);
  50         glEnable(GL_DEPTH_TEST);
  51
  52         setupCamera();
  53         moveCameraTo(cameraAnchor);
  54
  55         renderScene(currentScene, identity());
  56
  57         glFlush();
  58         glutSwapBuffers();
  59         frameRendered();
  60         glutPostRedisplay();
  61 }
  62
  63 static void renderScene(const Scene* scene, const Transform baseTransform) {
  64         if (!scene) {
  65                 return;
  66         }
  67
  68         Transform transform = multiply(scene->transform, baseTransform);
  69
  70         glMatrixMode(GL_MODELVIEW);
  71         glLoadTransposeMatrixf((const GLfloat*) &transform);
  72
  73         glDisable(GL_LIGHTING);
  74 #if SCENE_DEBUG_
  75         drawAxes();
  76 #endif // SCENE_DEBUG_
  77         glEnable(GL_LIGHTING);
  78
  79         if (scene->solid) {
  80                 glEnable(GL_LIGHT0);
  81                 glEnable(GL_TEXTURE_2D);
  82                 drawSolid(scene->solid);
  83                 glDisable(GL_TEXTURE_2D);
  84                 glDisable(GL_LIGHT0);
  85         }
  86
  87         for (size_t i = 0; i < scene->numChildren; ++i) {
  88                 renderScene(scene->children[i], transform);
  89         }
  90 }
  91
  92 static void setupCamera() {
  93         glMatrixMode(GL_PROJECTION);
  94         glLoadIdentity();
  95         glOrtho(-16.0,
  96                 16.0,
  97                 -16.0/viewportAspectRatio,
  98                 16.0/viewportAspectRatio,
  99                 -128.0,
 100                 128.0);
 101         glRotatef(45.0f, 1.0f, 0.0f, 0.0f);
 102         glRotatef(45.0f, 0.0f, 1.0f, 0.0f);
 103 }
 104
 105 static void moveCameraTo(const Scene* anchor) {
 106         glMatrixMode(GL_PROJECTION);
 107         Vector3D pos = translationOf(worldTransform(anchor));
 108         glTranslatef(-pos.x, -pos.y, -pos.z);
 109 }
 110
 111 static void drawAxes() {
 112         glMatrixMode(GL_MODELVIEW);
 113         // X axis
 114         glColor3f(1.0f, 0.0f, 0.0f);
 115         glBegin(GL_LINES);
 116         glVertex3f(0.0f, 0.0f, 0.0f);
 117         glVertex3f(AXIS_RADIUS, 0.0f, 0.0f);
 118         glEnd();
 119         // Y axis
 120         glColor3f(0.0f, 1.0f, 0.0f);
 121         glBegin(GL_LINES);
 122         glVertex3f(0.0f, 0.0f, 0.0f);
 123         glVertex3f(0.0f, AXIS_RADIUS, 0.0f);
 124         glEnd();
 125         // Z axis
 126         glColor3f(0.0f, 0.0f, 1.0f);
 127         glBegin(GL_LINES);
 128         glVertex3f(0.0f, 0.0f, 0.0f);
 129         glVertex3f(0.0f, 0.0f, AXIS_RADIUS);
 130         glEnd();
 131 }
 132
 133 #if RENDER_DEBUG_
 134 static GLfloat ab(GLfloat a) {
 135         return a < 0 ? -a : a;
 136 }
 137 #endif // RENDER_DEBUG_
 138
 139 static void drawSolid(const Solid* solid) {
 140         if (solid == NULL) {
 141                 return;
 142         }
 143
 144         glMatrixMode(GL_MODELVIEW);
 145         glColor3f(0.5f, 1.0f, 0.0f);
 146
 147         for (size_t meshIndex = 0; meshIndex < solid->numMeshes; ++meshIndex) {
 148                 const Mesh mesh = solid->meshes[meshIndex];
 149                 glBindTexture(GL_TEXTURE_2D,
 150                               solid->materials[mesh.materialIndex].textureId);
 151                 bool hasNormals = mesh.normals != NULL;
 152                 bool hasTextureCoords = mesh.textureCoords != NULL;
 153
 154                 for (size_t faceIndex = 0; faceIndex < mesh.numFaces; ++faceIndex) {
 155                         const Face face = mesh.faces[faceIndex];
 156
 157 #if RENDER_DEBUG_
 158                         if (hasNormals) {
 159                                 glDisable(GL_LIGHTING);
 160                                 glDisable(GL_TEXTURE_2D);
 161                                 glBegin(GL_LINES);
 162                                 for (size_t i = 0; i < face.numIndices; ++i) {
 163                                         size_t vertIndex = face.indices[i];
 164                                         Vector3D vertex = mesh.vertices[vertIndex];
 165                                         Vector3D normal = mesh.normals[vertIndex];
 166                                         glColor3f(ab(normal.x), ab(normal.y), ab(normal.z));
 167                                         glVertex3f(vertex.x, vertex.y, vertex.z);
 168                                         glVertex3f(vertex.x + normal.x, vertex.y + normal.y, vertex.z + normal.z);
 169                                 }
 170                                 glEnd();
 171                                 glEnable(GL_TEXTURE_2D);
 172                                 glEnable(GL_LIGHTING);
 173                         }
 174 #endif // RENDER_DEBUG_
 175
 176                         GLenum faceMode;
 177                         switch (face.numIndices) {
 178                                 case 1: faceMode = GL_POINTS; break;
 179                                 case 2: faceMode = GL_LINES; break;
 180                                 case 3: faceMode = GL_TRIANGLES; break;
 181                                 default: faceMode = GL_POLYGON; break;
 182                         }
 183
 184                         glBegin(faceMode);
 185
 186                         for (size_t i = 0; i < face.numIndices; ++i) {
 187                                 size_t vertIndex = face.indices[i];
 188                                 if (hasNormals) {
 189                                         if (hasTextureCoords) {
 190                                                 Vector3D coords = mesh.textureCoords[vertIndex];
 191                                                 glTexCoord2f(coords.x, coords.y);
 192                                         }
 193                                         Vector3D normal = mesh.normals[vertIndex];
 194                                         glNormal3f(normal.x, normal.y, normal.z);
 195                                 }
 196                                 Vector3D vertex = mesh.vertices[vertIndex];
 197                                 glVertex3f(vertex.x, vertex.y, vertex.z);
 198                         }
 199
 200                         glEnd();
 201                 }
 202         }
 203         glBindTexture(GL_TEXTURE_2D, 0);
 204 }