1 /*
2 * Copyright (C) 2009 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 // OpenGL ES 2.0 code
18
19 #include <jni.h>
20 #include <android/log.h>
21
22 #include <GLES2/gl2.h>
23 #include <GLES2/gl2ext.h>
24
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <math.h>
28
29 #define LOG_TAG "libgl2jni"
30 #define LOGI(...) __android_log_print(ANDROID_LOG_INFO,LOG_TAG,__VA_ARGS__)
31 #define LOGE(...) __android_log_print(ANDROID_LOG_ERROR,LOG_TAG,__VA_ARGS__)
32
printGLString(const char * name,GLenum s)33 static void printGLString(const char *name, GLenum s) {
34 const char *v = (const char *) glGetString(s);
35 LOGI("GL %s = %s\n", name, v);
36 }
37
checkGlError(const char * op)38 static void checkGlError(const char* op) {
39 for (GLint error = glGetError(); error; error
40 = glGetError()) {
41 LOGI("after %s() glError (0x%x)\n", op, error);
42 }
43 }
44
45 static const char gVertexShader[] = "attribute vec4 vPosition;\n"
46 "void main() {\n"
47 " gl_Position = vPosition;\n"
48 "}\n";
49
50 static const char gFragmentShader[] = "precision mediump float;\n"
51 "void main() {\n"
52 " gl_FragColor = vec4(0.0, 1.0, 0.0, 1.0);\n"
53 "}\n";
54
loadShader(GLenum shaderType,const char * pSource)55 GLuint loadShader(GLenum shaderType, const char* pSource) {
56 GLuint shader = glCreateShader(shaderType);
57 if (shader) {
58 glShaderSource(shader, 1, &pSource, NULL);
59 glCompileShader(shader);
60 GLint compiled = 0;
61 glGetShaderiv(shader, GL_COMPILE_STATUS, &compiled);
62 if (!compiled) {
63 GLint infoLen = 0;
64 glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &infoLen);
65 if (infoLen) {
66 char* buf = (char*) malloc(infoLen);
67 if (buf) {
68 glGetShaderInfoLog(shader, infoLen, NULL, buf);
69 LOGE("Could not compile shader %d:\n%s\n",
70 shaderType, buf);
71 free(buf);
72 }
73 glDeleteShader(shader);
74 shader = 0;
75 }
76 }
77 }
78 return shader;
79 }
80
createProgram(const char * pVertexSource,const char * pFragmentSource)81 GLuint createProgram(const char* pVertexSource, const char* pFragmentSource) {
82 GLuint vertexShader = loadShader(GL_VERTEX_SHADER, pVertexSource);
83 if (!vertexShader) {
84 return 0;
85 }
86
87 GLuint pixelShader = loadShader(GL_FRAGMENT_SHADER, pFragmentSource);
88 if (!pixelShader) {
89 return 0;
90 }
91
92 GLuint program = glCreateProgram();
93 if (program) {
94 glAttachShader(program, vertexShader);
95 checkGlError("glAttachShader");
96 glAttachShader(program, pixelShader);
97 checkGlError("glAttachShader");
98 glLinkProgram(program);
99 GLint linkStatus = GL_FALSE;
100 glGetProgramiv(program, GL_LINK_STATUS, &linkStatus);
101 if (linkStatus != GL_TRUE) {
102 GLint bufLength = 0;
103 glGetProgramiv(program, GL_INFO_LOG_LENGTH, &bufLength);
104 if (bufLength) {
105 char* buf = (char*) malloc(bufLength);
106 if (buf) {
107 glGetProgramInfoLog(program, bufLength, NULL, buf);
108 LOGE("Could not link program:\n%s\n", buf);
109 free(buf);
110 }
111 }
112 glDeleteProgram(program);
113 program = 0;
114 }
115 }
116 return program;
117 }
118
119 GLuint gProgram;
120 GLuint gvPositionHandle;
121
setupGraphics(int w,int h)122 bool setupGraphics(int w, int h) {
123 printGLString("Version", GL_VERSION);
124 printGLString("Vendor", GL_VENDOR);
125 printGLString("Renderer", GL_RENDERER);
126 printGLString("Extensions", GL_EXTENSIONS);
127
128 LOGI("setupGraphics(%d, %d)", w, h);
129 gProgram = createProgram(gVertexShader, gFragmentShader);
130 if (!gProgram) {
131 LOGE("Could not create program.");
132 return false;
133 }
134 gvPositionHandle = glGetAttribLocation(gProgram, "vPosition");
135 checkGlError("glGetAttribLocation");
136 LOGI("glGetAttribLocation(\"vPosition\") = %d\n",
137 gvPositionHandle);
138
139 glViewport(0, 0, w, h);
140 checkGlError("glViewport");
141 return true;
142 }
143
144 const GLfloat gTriangleVertices[] = { 0.0f, 0.5f, -0.5f, -0.5f,
145 0.5f, -0.5f };
146
renderFrame()147 void renderFrame() {
148 static float grey;
149 grey += 0.01f;
150 if (grey > 1.0f) {
151 grey = 0.0f;
152 }
153 glClearColor(grey, grey, grey, 1.0f);
154 checkGlError("glClearColor");
155 glClear( GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
156 checkGlError("glClear");
157
158 glUseProgram(gProgram);
159 checkGlError("glUseProgram");
160
161 glVertexAttribPointer(gvPositionHandle, 2, GL_FLOAT, GL_FALSE, 0, gTriangleVertices);
162 checkGlError("glVertexAttribPointer");
163 glEnableVertexAttribArray(gvPositionHandle);
164 checkGlError("glEnableVertexAttribArray");
165 glDrawArrays(GL_TRIANGLES, 0, 3);
166 checkGlError("glDrawArrays");
167 }
168
169 extern "C" {
170 JNIEXPORT void JNICALL Java_com_android_gl2jni_GL2JNILib_init(JNIEnv * env, jobject obj, jint width, jint height);
171 JNIEXPORT void JNICALL Java_com_android_gl2jni_GL2JNILib_step(JNIEnv * env, jobject obj);
172 };
173
Java_com_android_gl2jni_GL2JNILib_init(JNIEnv * env,jobject obj,jint width,jint height)174 JNIEXPORT void JNICALL Java_com_android_gl2jni_GL2JNILib_init(JNIEnv * env, jobject obj, jint width, jint height)
175 {
176 setupGraphics(width, height);
177 }
178
Java_com_android_gl2jni_GL2JNILib_step(JNIEnv * env,jobject obj)179 JNIEXPORT void JNICALL Java_com_android_gl2jni_GL2JNILib_step(JNIEnv * env, jobject obj)
180 {
181 renderFrame();
182 }
183