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[] =
46 "attribute vec4 vPosition;\n"
47 "void main() {\n"
48 " gl_Position = vPosition;\n"
49 "}\n";
50
51 static const char gFragmentShader[] =
52 "precision mediump float;\n"
53 "void main() {\n"
54 " gl_FragColor = vec4(0.0, 1.0, 0.0, 1.0);\n"
55 "}\n";
56
loadShader(GLenum shaderType,const char * pSource)57 GLuint loadShader(GLenum shaderType, const char* pSource) {
58 GLuint shader = glCreateShader(shaderType);
59 if (shader) {
60 glShaderSource(shader, 1, &pSource, NULL);
61 glCompileShader(shader);
62 GLint compiled = 0;
63 glGetShaderiv(shader, GL_COMPILE_STATUS, &compiled);
64 if (!compiled) {
65 GLint infoLen = 0;
66 glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &infoLen);
67 if (infoLen) {
68 char* buf = (char*) malloc(infoLen);
69 if (buf) {
70 glGetShaderInfoLog(shader, infoLen, NULL, buf);
71 LOGE("Could not compile shader %d:\n%s\n",
72 shaderType, buf);
73 free(buf);
74 }
75 glDeleteShader(shader);
76 shader = 0;
77 }
78 }
79 }
80 return shader;
81 }
82
createProgram(const char * pVertexSource,const char * pFragmentSource)83 GLuint createProgram(const char* pVertexSource, const char* pFragmentSource) {
84 GLuint vertexShader = loadShader(GL_VERTEX_SHADER, pVertexSource);
85 if (!vertexShader) {
86 return 0;
87 }
88
89 GLuint pixelShader = loadShader(GL_FRAGMENT_SHADER, pFragmentSource);
90 if (!pixelShader) {
91 return 0;
92 }
93
94 GLuint program = glCreateProgram();
95 if (program) {
96 glAttachShader(program, vertexShader);
97 checkGlError("glAttachShader");
98 glAttachShader(program, pixelShader);
99 checkGlError("glAttachShader");
100 glLinkProgram(program);
101 GLint linkStatus = GL_FALSE;
102 glGetProgramiv(program, GL_LINK_STATUS, &linkStatus);
103 if (linkStatus != GL_TRUE) {
104 GLint bufLength = 0;
105 glGetProgramiv(program, GL_INFO_LOG_LENGTH, &bufLength);
106 if (bufLength) {
107 char* buf = (char*) malloc(bufLength);
108 if (buf) {
109 glGetProgramInfoLog(program, bufLength, NULL, buf);
110 LOGE("Could not link program:\n%s\n", buf);
111 free(buf);
112 }
113 }
114 glDeleteProgram(program);
115 program = 0;
116 }
117 }
118 return program;
119 }
120
121 GLuint gProgram;
122 GLuint gvPositionHandle;
123
setupGraphics(int w,int h)124 bool setupGraphics(int w, int h) {
125 printGLString("Version", GL_VERSION);
126 printGLString("Vendor", GL_VENDOR);
127 printGLString("Renderer", GL_RENDERER);
128 printGLString("Extensions", GL_EXTENSIONS);
129
130 LOGI("setupGraphics(%d, %d)", w, h);
131 gProgram = createProgram(gVertexShader, gFragmentShader);
132 if (!gProgram) {
133 LOGE("Could not create program.");
134 return false;
135 }
136 gvPositionHandle = glGetAttribLocation(gProgram, "vPosition");
137 checkGlError("glGetAttribLocation");
138 LOGI("glGetAttribLocation(\"vPosition\") = %d\n",
139 gvPositionHandle);
140
141 glViewport(0, 0, w, h);
142 checkGlError("glViewport");
143 return true;
144 }
145
146 const GLfloat gTriangleVertices[] = { 0.0f, 0.5f, -0.5f, -0.5f,
147 0.5f, -0.5f };
148
renderFrame()149 void renderFrame() {
150 static float grey;
151 grey += 0.01f;
152 if (grey > 1.0f) {
153 grey = 0.0f;
154 }
155 glClearColor(grey, grey, grey, 1.0f);
156 checkGlError("glClearColor");
157 glClear( GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
158 checkGlError("glClear");
159
160 glUseProgram(gProgram);
161 checkGlError("glUseProgram");
162
163 glVertexAttribPointer(gvPositionHandle, 2, GL_FLOAT, GL_FALSE, 0, gTriangleVertices);
164 checkGlError("glVertexAttribPointer");
165 glEnableVertexAttribArray(gvPositionHandle);
166 checkGlError("glEnableVertexAttribArray");
167 glDrawArrays(GL_TRIANGLES, 0, 3);
168 checkGlError("glDrawArrays");
169 }
170
171 extern "C" {
172 JNIEXPORT void JNICALL Java_com_android_gl2jni_GL2JNILib_init(JNIEnv * env, jobject obj, jint width, jint height);
173 JNIEXPORT void JNICALL Java_com_android_gl2jni_GL2JNILib_step(JNIEnv * env, jobject obj);
174 };
175
Java_com_android_gl2jni_GL2JNILib_init(JNIEnv * env,jobject obj,jint width,jint height)176 JNIEXPORT void JNICALL Java_com_android_gl2jni_GL2JNILib_init(JNIEnv * env, jobject obj, jint width, jint height)
177 {
178 setupGraphics(width, height);
179 }
180
Java_com_android_gl2jni_GL2JNILib_step(JNIEnv * env,jobject obj)181 JNIEXPORT void JNICALL Java_com_android_gl2jni_GL2JNILib_step(JNIEnv * env, jobject obj)
182 {
183 renderFrame();
184 }
185