src/engine/render.c

   1 #include <GL/glut.h>
   2 #include <stdbool.h>
   3
   4 #include "game/level.h"
   5 #include "game/player.h"
   6
   7 #include "geometry.h"
   8 #include "performance.h"
   9
  10 const float AXIS_RADIUS = 5.0f;
  11
  12 static void setupCamera();
  13 static void moveCameraTo(const Vector3D pos);
  14 static void drawAxes();
  15 static void renderBlockGrid(const BlockGrid grid);
  16 static void renderCharacter(const Character* character, const Vector3D pos);
  17 static void drawAsset3D(const Asset3D* asset3D);
  18
  19 float viewportAspectRatio = 1.0f;
  20
  21
  22
  23 void initRender() {
  24         glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
  25
  26         GLfloat light0_ambient[] = {0.1f, 0.1f, 0.1f, 1.0f};
  27         GLfloat light0_diffuse[] = {1.0f, 1.0f, 1.0f, 1.0f};
  28         GLfloat light0_specular[] = {0.96f, 0.98f, 1.0f, 1.0f};
  29         GLfloat light0_position[] = {5.0f, 10.0f, 5.0f, 0.0f}; // (w == 0.0f) == directional
  30
  31         glLightfv(GL_LIGHT0, GL_AMBIENT, light0_ambient);
  32         glLightfv(GL_LIGHT0, GL_DIFFUSE, light0_diffuse);
  33         glLightfv(GL_LIGHT0, GL_SPECULAR, light0_specular);
  34         glLightfv(GL_LIGHT0, GL_POSITION, light0_position);
  35
  36         glLightf(GL_LIGHT0, GL_CONSTANT_ATTENUATION, 1.0f);
  37         glLightf(GL_LIGHT0, GL_LINEAR_ATTENUATION, 0.05f);
  38         glLightf(GL_LIGHT0, GL_QUADRATIC_ATTENUATION, 0.005f);
  39 }
  40
  41 void renderScene() {
  42         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  43
  44         glEnable(GL_NORMALIZE);
  45         glEnable(GL_CULL_FACE);
  46         glEnable(GL_DEPTH_TEST);
  47
  48         setupCamera();
  49         moveCameraTo(playerPos);
  50
  51         glDisable(GL_LIGHTING);
  52         drawAxes();
  53         glEnable(GL_LIGHTING);
  54
  55         glEnable(GL_LIGHT0);
  56         glEnable(GL_TEXTURE_2D);
  57         renderBlockGrid(levelGrid);
  58         renderCharacter(&playerCharacter, playerPos);
  59         glDisable(GL_TEXTURE_2D);
  60         glDisable(GL_LIGHT0);
  61
  62         glFlush();
  63         glutSwapBuffers();
  64         frameRendered();
  65         glutPostRedisplay();
  66 }
  67
  68 static void setupCamera() {
  69         glMatrixMode(GL_PROJECTION);
  70         glLoadIdentity();
  71         glOrtho(-16.0,
  72                 16.0,
  73                 -16.0/viewportAspectRatio,
  74                 16.0/viewportAspectRatio,
  75                 -128.0,
  76                 128.0);
  77         glRotatef(45.0f, 1.0f, 0.0f, 0.0f);
  78         glRotatef(45.0f, 0.0f, 1.0f, 0.0f);
  79 }
  80
  81 static void moveCameraTo(const Vector3D pos) {
  82         glMatrixMode(GL_PROJECTION);
  83         glTranslatef(-pos.x, -pos.y, -pos.z);
  84 }
  85
  86 static void drawAxes() {
  87         glMatrixMode(GL_MODELVIEW);
  88         // X axis
  89         glColor3f(1.0f, 0.0f, 0.0f);
  90         glBegin(GL_LINES);
  91         glVertex3f(0.0f, 0.0f, 0.0f);
  92         glVertex3f(AXIS_RADIUS, 0.0f, 0.0f);
  93         glEnd();
  94         // Y axis
  95         glColor3f(0.0f, 1.0f, 0.0f);
  96         glBegin(GL_LINES);
  97         glVertex3f(0.0f, 0.0f, 0.0f);
  98         glVertex3f(0.0f, AXIS_RADIUS, 0.0f);
  99         glEnd();
 100         // Z axis
 101         glColor3f(0.0f, 0.0f, 1.0f);
 102         glBegin(GL_LINES);
 103         glVertex3f(0.0f, 0.0f, 0.0f);
 104         glVertex3f(0.0f, 0.0f, AXIS_RADIUS);
 105         glEnd();
 106 }
 107
 108 static void renderBlockGrid(const BlockGrid grid) {
 109         glMatrixMode(GL_MODELVIEW);
 110         for (int z = 0; z < grid.depth; ++z) {
 111                 glLoadIdentity();
 112                 glTranslatef(0.0f, 0.0f, z * BLOCKGRID_CELL_SIZE);
 113                 for (int x = 0; x < grid.width; ++x) {
 114                         drawAsset3D(getBlockFromGrid(grid, x, z)->asset3D);
 115                         glTranslatef(BLOCKGRID_CELL_SIZE, 0.0f, 0.0f);
 116                 }
 117         }
 118         glLoadIdentity();
 119 }
 120
 121 static void renderCharacter(const Character* character, const Vector3D pos) {
 122         glMatrixMode(GL_MODELVIEW);
 123         glTranslatef(pos.x, pos.y, pos.z);
 124         drawAsset3D(character->asset3D);
 125         glLoadIdentity();
 126 }
 127
 128 static void drawAsset3D(const Asset3D* asset3D) {
 129         if (asset3D == NULL) {
 130                 return;
 131         }
 132
 133         glMatrixMode(GL_MODELVIEW);
 134         glColor3f(0.5f, 1.0f, 0.0f);
 135
 136         for (size_t meshIndex = 0; meshIndex < asset3D->numMeshes; ++meshIndex) {
 137                 const Mesh mesh = asset3D->meshes[meshIndex];
 138                 glBindTexture(GL_TEXTURE_2D,
 139                               asset3D->materials[mesh.materialIndex].textureId);
 140                 bool hasNormals = mesh.normals != NULL;
 141                 bool hasTextureCoords = mesh.textureCoords != NULL;
 142
 143                 for (size_t faceIndex = 0; faceIndex < mesh.numFaces; ++faceIndex) {
 144                         const Face face = mesh.faces[faceIndex];
 145
 146                         GLenum faceMode;
 147                         switch (face.numIndices) {
 148                                 case 1: faceMode = GL_POINTS; break;
 149                                 case 2: faceMode = GL_LINES; break;
 150                                 case 3: faceMode = GL_TRIANGLES; break;
 151                                 default: faceMode = GL_POLYGON; break;
 152                         }
 153
 154                         glBegin(faceMode);
 155
 156                         for (size_t i = 0; i < face.numIndices; ++i) {
 157                                 unsigned int vertIndex = face.indices[i];
 158                                 if (hasNormals) {
 159                                         if (hasTextureCoords) {
 160                                                 Vector3D coords = mesh.textureCoords[vertIndex];
 161                                                 glTexCoord2f(coords.x, coords.y);
 162                                         }
 163                                         Vector3D normal = mesh.normals[vertIndex];
 164                                         glNormal3f(normal.x, normal.y, normal.z);
 165                                 }
 166                                 Vector3D vertex = mesh.vertices[vertIndex];
 167                                 glVertex3f(vertex.x, vertex.y, vertex.z);
 168                         }
 169
 170                         glEnd();
 171                 }
 172         }
 173         glBindTexture(GL_TEXTURE_2D, 0);
 174 }