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*, const Transform baseTransform);
  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, identity());
  51
  52         glFlush();
  53         glutSwapBuffers();
  54         frameRendered();
  55         glutPostRedisplay();
  56 }
  57
  58 static void renderScene(const Scene* scene, const Transform baseTransform) {
  59         if (!scene) {
  60                 return;
  61         }
  62
  63         Transform transform = multiply(scene->transform, baseTransform);
  64
  65         glMatrixMode(GL_MODELVIEW);
  66         glLoadTransposeMatrixf((const GLfloat*) &transform);
  67
  68         glDisable(GL_LIGHTING);
  69         drawAxes();
  70         glEnable(GL_LIGHTING);
  71
  72         if (scene->solid) {
  73                 glEnable(GL_LIGHT0);
  74                 glEnable(GL_TEXTURE_2D);
  75                 drawSolid(scene->solid);
  76                 glDisable(GL_TEXTURE_2D);
  77                 glDisable(GL_LIGHT0);
  78         }
  79
  80         for (size_t i = 0; i < scene->numChildren; ++i) {
  81                 renderScene(scene->children[i], transform);
  82         }
  83 }
  84
  85 static void setupCamera() {
  86         glMatrixMode(GL_PROJECTION);
  87         glLoadIdentity();
  88         glOrtho(-16.0,
  89                 16.0,
  90                 -16.0/viewportAspectRatio,
  91                 16.0/viewportAspectRatio,
  92                 -128.0,
  93                 128.0);
  94         glRotatef(45.0f, 1.0f, 0.0f, 0.0f);
  95         glRotatef(45.0f, 0.0f, 1.0f, 0.0f);
  96 }
  97
  98 static void moveCameraTo(const Scene* anchor) {
  99         glMatrixMode(GL_PROJECTION);
 100         // TODO This needs to account for parent nodes as well
 101         Vector3D pos = translationOf(worldTransform(anchor));
 102         glTranslatef(-pos.x, -pos.y, -pos.z);
 103 }
 104
 105 static void drawAxes() {
 106         glMatrixMode(GL_MODELVIEW);
 107         // X axis
 108         glColor3f(1.0f, 0.0f, 0.0f);
 109         glBegin(GL_LINES);
 110         glVertex3f(0.0f, 0.0f, 0.0f);
 111         glVertex3f(AXIS_RADIUS, 0.0f, 0.0f);
 112         glEnd();
 113         // Y axis
 114         glColor3f(0.0f, 1.0f, 0.0f);
 115         glBegin(GL_LINES);
 116         glVertex3f(0.0f, 0.0f, 0.0f);
 117         glVertex3f(0.0f, AXIS_RADIUS, 0.0f);
 118         glEnd();
 119         // Z axis
 120         glColor3f(0.0f, 0.0f, 1.0f);
 121         glBegin(GL_LINES);
 122         glVertex3f(0.0f, 0.0f, 0.0f);
 123         glVertex3f(0.0f, 0.0f, AXIS_RADIUS);
 124         glEnd();
 125 }
 126
 127 static void drawSolid(const Solid* solid) {
 128         if (solid == NULL) {
 129                 return;
 130         }
 131
 132         glMatrixMode(GL_MODELVIEW);
 133         glColor3f(0.5f, 1.0f, 0.0f);
 134
 135         for (size_t meshIndex = 0; meshIndex < solid->numMeshes; ++meshIndex) {
 136                 const Mesh mesh = solid->meshes[meshIndex];
 137                 glBindTexture(GL_TEXTURE_2D,
 138                               solid->materials[mesh.materialIndex].textureId);
 139                 bool hasNormals = mesh.normals != NULL;
 140                 bool hasTextureCoords = mesh.textureCoords != NULL;
 141
 142                 for (size_t faceIndex = 0; faceIndex < mesh.numFaces; ++faceIndex) {
 143                         const Face face = mesh.faces[faceIndex];
 144
 145                         GLenum faceMode;
 146                         switch (face.numIndices) {
 147                                 case 1: faceMode = GL_POINTS; break;
 148                                 case 2: faceMode = GL_LINES; break;
 149                                 case 3: faceMode = GL_TRIANGLES; break;
 150                                 default: faceMode = GL_POLYGON; break;
 151                         }
 152
 153                         glBegin(faceMode);
 154
 155                         for (size_t i = 0; i < face.numIndices; ++i) {
 156                                 size_t vertIndex = face.indices[i];
 157                                 if (hasNormals) {
 158                                         if (hasTextureCoords) {
 159                                                 Vector3D coords = mesh.textureCoords[vertIndex];
 160                                                 glTexCoord2f(coords.x, coords.y);
 161                                         }
 162                                         Vector3D normal = mesh.normals[vertIndex];
 163                                         glNormal3f(normal.x, normal.y, normal.z);
 164                                 }
 165                                 Vector3D vertex = mesh.vertices[vertIndex];
 166                                 glVertex3f(vertex.x, vertex.y, vertex.z);
 167                         }
 168
 169                         glEnd();
 170                 }
 171         }
 172         glBindTexture(GL_TEXTURE_2D, 0);
 173 }