143 lines
3.9 KiB
C
143 lines
3.9 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include "GL/gl.h"
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#include "GL/glu.h"
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#include "GL/glkos.h"
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#define TERRAIN_SIZE 100
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#define TERRAIN_SCALE 1.0f
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#define TERRAIN_HEIGHT_SCALE 1.0f
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typedef struct {
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float x, y, z;
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} Vec3;
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Vec3 vertices[TERRAIN_SIZE * TERRAIN_SIZE];
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unsigned int indices[TERRAIN_SIZE * TERRAIN_SIZE * 2];
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Vec3 normals[TERRAIN_SIZE * TERRAIN_SIZE];
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void GenerateTerrain() {
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const float OFFSET = (-TERRAIN_SIZE * TERRAIN_SCALE) / 2.0f;
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unsigned int j = 0;
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unsigned int z, x;
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for(z = 0; z < TERRAIN_SIZE; ++z) {
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for(x = 0; x < TERRAIN_SIZE; ++x) {
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unsigned int i = (z * TERRAIN_SIZE) + x;
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vertices[i].x = (x * TERRAIN_SCALE) + OFFSET;
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vertices[i].z = (z * TERRAIN_SCALE) + OFFSET;
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vertices[i].y = (float)rand() / (float)(RAND_MAX / TERRAIN_HEIGHT_SCALE);
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normals[i].x = normals[i].z = 0.0f;
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normals[i].y = 1.0f;
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if(z > 0) {
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indices[j++] = (i - TERRAIN_SIZE);
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indices[j++] = i;
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}
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}
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}
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}
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/* A general OpenGL initialization function. Sets all of the initial parameters. */
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void InitGL(int Width, int Height) // We call this right after our OpenGL window is created.
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{
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glClearColor(0.0f, 0.0f, 0.0f, 0.0f); // This Will Clear The Background Color To Black
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glClearDepth(1.0); // Enables Clearing Of The Depth Buffer
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glDepthFunc(GL_LEQUAL); // The Type Of Depth Test To Do
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glEnable(GL_DEPTH_TEST); // Enables Depth Testing
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glShadeModel(GL_SMOOTH); // Enables Smooth Color Shading
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity(); // Reset The Projection Matrix
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gluPerspective(45.0f,(GLfloat)Width/(GLfloat)Height,0.1f,100.0f); // Calculate The Aspect Ratio Of The Window
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glMatrixMode(GL_MODELVIEW);
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GenerateTerrain();
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/* glEnable(GL_LIGHTING);
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glEnable(GL_LIGHT0);
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glDisable(GL_BLEND);
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GLfloat mat_diffuse[] = {0.0, 1.0, 0.0, 1.0};
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GLfloat mat_specular[] = { 1.0, 1.0, 1.0, 1.0 };
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GLfloat mat_shininess[] = { 50.0 };
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GLfloat light_position[] = { 1.0, -1.0, 0.0, 0.0 };
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glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, mat_diffuse);
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glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular);
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glMaterialfv(GL_FRONT, GL_SHININESS, mat_shininess);
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glLightfv(GL_LIGHT0, GL_POSITION, light_position); */
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fprintf(stderr, "Generated terrain\n");
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}
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/* The function called when our window is resized (which shouldn't happen, because we're fullscreen) */
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void ReSizeGLScene(int Width, int Height)
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{
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if (Height == 0) // Prevent A Divide By Zero If The Window Is Too Small
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Height = 1;
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glViewport(0, 0, Width, Height); // Reset The Current Viewport And Perspective Transformation
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity();
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gluPerspective(45.0f,(GLfloat)Width/(GLfloat)Height,0.1f,100.0f);
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glMatrixMode(GL_MODELVIEW);
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}
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/* The main drawing function. */
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void DrawGLScene()
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{
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glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear The Screen And The Depth Buffer
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glLoadIdentity(); // Reset The View
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glDisable(GL_CULL_FACE);
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glTranslatef(0.0f, -1.0f, 0.0f);
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static float x = 0.0f;
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x += 1.0f;
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glRotatef(x, 0, 1.0f, 0);
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glEnableClientState(GL_VERTEX_ARRAY);
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glEnableClientState(GL_NORMAL_ARRAY);
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glNormalPointer(GL_FLOAT, 0, normals);
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glVertexPointer(3, GL_FLOAT, 0, &vertices[0].x);
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unsigned int z;
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for(z = 0; z < TERRAIN_SIZE; ++z) {
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glDrawElements(
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GL_TRIANGLE_STRIP,
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TERRAIN_SIZE * 2,
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GL_UNSIGNED_INT,
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indices + (z * (TERRAIN_SIZE * 2))
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);
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}
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// swap buffers to display, since we're double buffered.
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glKosSwapBuffers();
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}
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int main(int argc, char **argv)
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{
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glKosInit();
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InitGL(640, 480);
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ReSizeGLScene(640, 480);
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while(1) {
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DrawGLScene();
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}
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return 0;
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}
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