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