src/engine/render.c

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