glstuff

experiments with opengl2/ogles2/sdl
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test1.cc (2632B)

      1 /* Copyright 2013 Brian Swetland <swetland@frotz.net>
      2  *
      3  * Licensed under the Apache License, Version 2.0 (the "License");
      4  * you may not use this file except in compliance with the License.
      5  * You may obtain a copy of the License at
      6  *
      7  *     http://www.apache.org/licenses/LICENSE-2.0
      8  *
      9  * Unless required by applicable law or agreed to in writing, software
     10  * distributed under the License is distributed on an "AS IS" BASIS,
     11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     12  * See the License for the specific language governing permissions and
     13  * limitations under the License.
     14  */
     15 
     16 #include <stdio.h>
     17 #include <stdlib.h>
     18 #include <unistd.h>
     19 
     20 #include "app.h"
     21 #include "util.h"
     22 #include "matrix.h"
     23 #include "program.h"
     24 
     25 class TestApp : public App {
     26 public:
     27 	int init(void);
     28 	int render(void);
     29 
     30 private:
     31 	void *texdata;
     32 	unsigned texw, texh;
     33 
     34 	GLuint tex0;
     35 	GLuint aVertex, aTexCoord;
     36 	GLuint uMVP, uTexture;
     37  
     38 	mat4 MVP;
     39 	Program pgm;
     40 };
     41 
     42 static GLfloat verts[] = {
     43 	-0.5f, -0.5f, 0.0f,
     44 	-0.5f, 0.5f, 0.0f,
     45 	0.5f, -0.5f, 0.0f,
     46 	0.5f, 0.5f, 0.0f,	
     47 };
     48 
     49 static GLfloat texcoords[] = {
     50 	0.0, 0.0,
     51 	0.0, 1.0,
     52 	1.0, 0.0,
     53 	1.0, 1.0,
     54 };
     55 
     56 int TestApp::init(void) {
     57 	if (!(texdata = load_png_rgba("texture1.png", &texw, &texh, 1))) 
     58 		return -1;
     59 
     60 	MVP.setOrtho(-2.66, 2.66, -2, 2, 1, -1);
     61 
     62 	glViewport(0, 0, width(), height());
     63 	glClearColor(0, 0, 0, 0);
     64 	glClearDepth(1.0f);
     65 
     66 	if (pgm.compile("test1.vs","test1.fs"))
     67 		return -1;
     68 
     69 	aVertex = pgm.getAttribID("aVertex");
     70 	aTexCoord = pgm.getAttribID("aTexCoord");
     71 	uMVP = pgm.getUniformID("uMVP");
     72 	uTexture = pgm.getUniformID("uTexture");
     73 
     74 	if(glGetError() != GL_NO_ERROR) fprintf(stderr,"OOPS!\n");
     75 
     76 	glEnable(GL_TEXTURE_2D);
     77 
     78 	glGenTextures(1, &tex0);
     79 	glBindTexture(GL_TEXTURE_2D, tex0);
     80 	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texw, texh, 0, GL_RGBA,
     81 		GL_UNSIGNED_BYTE, texdata);
     82 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
     83 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
     84 
     85 	return 0;
     86 }
     87 
     88 int TestApp::render() {
     89 	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
     90 	glLoadIdentity();
     91 	pgm.use();
     92 
     93 	glActiveTexture(GL_TEXTURE0);
     94 	glBindTexture(GL_TEXTURE_2D, tex0);
     95 
     96 	glUniformMatrix4fv(uMVP, 1, GL_FALSE, MVP);
     97 	glUniform1i(uTexture, 0);
     98 
     99 	glVertexAttribPointer(aVertex, 3, GL_FLOAT, GL_FALSE, 0, verts);
    100 	glEnableVertexAttribArray(aVertex);
    101 
    102 	glVertexAttribPointer(aTexCoord, 2, GL_FLOAT, GL_FALSE, 0, texcoords);
    103 	glEnableVertexAttribArray(aTexCoord);
    104 
    105 	glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
    106 
    107 	return 0;
    108 }
    109 
    110 int main(int argc, char **argv) {
    111 	TestApp app;
    112 	app.setOptions(argc, argv);
    113 	return app.run();
    114 }