1 // OpenGL ES 2.0 code
2
3 #include <jni.h>
4 #define LOG_TAG "GL2JNI gl_code.cpp"
5 #include <utils/Log.h>
6
7 #include <EGL/egl.h>
8 #include <GLES2/gl2.h>
9 #include <GLES2/gl2ext.h>
10
11 #include <stdio.h>
12 #include <stdlib.h>
13 #include <math.h>
14
printGLString(const char * name,GLenum s)15 static void printGLString(const char *name, GLenum s) {
16 const char *v = (const char *) glGetString(s);
17 ALOGI("GL %s = %s\n", name, v);
18 }
19
checkGlError(const char * op)20 static void checkGlError(const char* op) {
21 for (GLint error = glGetError(); error; error
22 = glGetError()) {
23 ALOGI("after %s() glError (0x%x)\n", op, error);
24 }
25 }
26
27 static const char gVertexShader[] = "attribute vec4 vPosition;\n"
28 "void main() {\n"
29 " gl_Position = vPosition;\n"
30 "}\n";
31
32 static const char gFragmentShader[] = "precision mediump float;\n"
33 "void main() {\n"
34 " gl_FragColor = vec4(0.0, 1.0, 0.0, 1.0);\n"
35 "}\n";
36
loadShader(GLenum shaderType,const char * pSource)37 GLuint loadShader(GLenum shaderType, const char* pSource) {
38 GLuint shader = glCreateShader(shaderType);
39 if (shader) {
40 glShaderSource(shader, 1, &pSource, NULL);
41 glCompileShader(shader);
42 GLint compiled = 0;
43 glGetShaderiv(shader, GL_COMPILE_STATUS, &compiled);
44 if (!compiled) {
45 GLint infoLen = 0;
46 glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &infoLen);
47 if (infoLen) {
48 char* buf = (char*) malloc(infoLen);
49 if (buf) {
50 glGetShaderInfoLog(shader, infoLen, NULL, buf);
51 ALOGE("Could not compile shader %d:\n%s\n",
52 shaderType, buf);
53 free(buf);
54 }
55 glDeleteShader(shader);
56 shader = 0;
57 }
58 }
59 }
60 return shader;
61 }
62
createProgram(const char * pVertexSource,const char * pFragmentSource)63 GLuint createProgram(const char* pVertexSource, const char* pFragmentSource) {
64 GLuint vertexShader = loadShader(GL_VERTEX_SHADER, pVertexSource);
65 if (!vertexShader) {
66 return 0;
67 }
68
69 GLuint pixelShader = loadShader(GL_FRAGMENT_SHADER, pFragmentSource);
70 if (!pixelShader) {
71 return 0;
72 }
73
74 GLuint program = glCreateProgram();
75 if (program) {
76 glAttachShader(program, vertexShader);
77 checkGlError("glAttachShader");
78 glAttachShader(program, pixelShader);
79 checkGlError("glAttachShader");
80 glLinkProgram(program);
81 GLint linkStatus = GL_FALSE;
82 glGetProgramiv(program, GL_LINK_STATUS, &linkStatus);
83 if (linkStatus != GL_TRUE) {
84 GLint bufLength = 0;
85 glGetProgramiv(program, GL_INFO_LOG_LENGTH, &bufLength);
86 if (bufLength) {
87 char* buf = (char*) malloc(bufLength);
88 if (buf) {
89 glGetProgramInfoLog(program, bufLength, NULL, buf);
90 ALOGE("Could not link program:\n%s\n", buf);
91 free(buf);
92 }
93 }
94 glDeleteProgram(program);
95 program = 0;
96 }
97 }
98 return program;
99 }
100
101 GLuint gProgram;
102 GLuint gvPositionHandle;
103
setupGraphics(int w,int h)104 bool setupGraphics(int w, int h) {
105 printGLString("Version", GL_VERSION);
106 printGLString("Vendor", GL_VENDOR);
107 printGLString("Renderer", GL_RENDERER);
108 printGLString("Extensions", GL_EXTENSIONS);
109
110 ALOGI("setupGraphics(%d, %d)", w, h);
111 gProgram = createProgram(gVertexShader, gFragmentShader);
112 if (!gProgram) {
113 ALOGE("Could not create program.");
114 return false;
115 }
116 gvPositionHandle = glGetAttribLocation(gProgram, "vPosition");
117 checkGlError("glGetAttribLocation");
118 ALOGI("glGetAttribLocation(\"vPosition\") = %d\n",
119 gvPositionHandle);
120
121 glViewport(0, 0, w, h);
122 checkGlError("glViewport");
123 return true;
124 }
125
126 const GLfloat gTriangleVertices[] = { 0.0f, 0.5f, -0.5f, -0.5f,
127 0.5f, -0.5f };
128
renderFrame()129 void renderFrame() {
130 static float grey;
131 grey += 0.01f;
132 if (grey > 1.0f) {
133 grey = 0.0f;
134 }
135 glClearColor(grey, grey, grey, 1.0f);
136 checkGlError("glClearColor");
137 glClear( GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
138 checkGlError("glClear");
139
140 glUseProgram(gProgram);
141 checkGlError("glUseProgram");
142
143 glVertexAttribPointer(gvPositionHandle, 2, GL_FLOAT, GL_FALSE, 0, gTriangleVertices);
144 checkGlError("glVertexAttribPointer");
145 glEnableVertexAttribArray(gvPositionHandle);
146 checkGlError("glEnableVertexAttribArray");
147 glDrawArrays(GL_TRIANGLES, 0, 3);
148 checkGlError("glDrawArrays");
149 }
150
151 extern "C" {
152 JNIEXPORT void JNICALL Java_com_android_gldual_GLDualLib_init(JNIEnv * env, jobject obj, jint width, jint height);
153 JNIEXPORT void JNICALL Java_com_android_gldual_GLDualLib_step(JNIEnv * env, jobject obj);
154 };
155
Java_com_android_gldual_GLDualLib_init(JNIEnv *,jobject,jint width,jint height)156 JNIEXPORT void JNICALL Java_com_android_gldual_GLDualLib_init(JNIEnv * /*env*/, jobject /*obj*/, jint width, jint height)
157 {
158 setupGraphics(width, height);
159 }
160
Java_com_android_gldual_GLDualLib_step(JNIEnv *,jobject)161 JNIEXPORT void JNICALL Java_com_android_gldual_GLDualLib_step(JNIEnv * /*env*/, jobject /*obj*/)
162 {
163 renderFrame();
164 }
165
166