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