代码基于Visual Studio 2019的模板。仅绘制背景颜色，而不绘制三角形。我尝试更改背景颜色，因为通过动态更改clearcolor来调用engine_draw_frame()，并且背景确实发生了变化。我试图通过生成缓冲区，将其绑定并使用glBufferData将数据复制到缓冲区来使用vbo，但仍然没有呈现三角形。
然后我尝试在相同的位置使用glVertexPointer之类的es1 api来绘制三角形。 es2 api调用有什么问题吗？
#include <malloc.h>
#include <stdlib.h>
#include <GLES2/gl2.h>
#define LOGI(...) ((void)__android_log_print(ANDROID_LOG_INFO, "AndroidProject1.NativeActivity", __VA_ARGS__))
#define LOGW(...) ((void)__android_log_print(ANDROID_LOG_WARN, "AndroidProject1.NativeActivity", __VA_ARGS__))
GLuint fragShader, vertShader, program;
void create_shaders(void)
{
static const char* fragShaderText =
"precision mediump float;\n"
"void main() {\n"
" gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);\n"
"}\n";
static const char* vertShaderText =
"attribute vec4 pos;\n"
"void main() {\n"
" gl_Position = pos;\n"
"}\n";
GLint stat;
fragShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragShader, 1, (const char**)&fragShaderText, NULL);
glCompileShader(fragShader);
glGetShaderiv(fragShader, GL_COMPILE_STATUS, &stat);
if (!stat) {
printf("Error: fragment shader did not compile!\n");
exit(1);
}
vertShader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertShader, 1, (const char**)&vertShaderText, NULL);
glCompileShader(vertShader);
glGetShaderiv(vertShader, GL_COMPILE_STATUS, &stat);
if (!stat) {
printf("Error: vertex shader did not compile!\n");
exit(1);
}
program = glCreateProgram();
glAttachShader(program, fragShader);
glAttachShader(program, vertShader);
glBindAttribLocation(program, 0, "pos");
glLinkProgram(program); /* needed to put attribs into effect */
glGetProgramiv(program, GL_LINK_STATUS, &stat);
if (!stat) {
char log[1000];
GLsizei len;
glGetProgramInfoLog(program, 1000, &len, log);
printf("Error: linking:\n%s\n", log);
exit(1);
}
glUseProgram(program);
}
struct saved_state {
float angle;
int32_t x;
int32_t y;
};
struct engine {
struct android_app* app;
ASensorManager* sensorManager;
const ASensor* accelerometerSensor;
ASensorEventQueue* sensorEventQueue;
int animating;
EGLDisplay display;
EGLSurface surface;
EGLContext context;
int32_t width;
int32_t height;
struct saved_state state;
};
static int engine_init_display(struct engine* engine) {
const EGLint attribs[] = {
EGL_SURFACE_TYPE, EGL_WINDOW_BIT,
EGL_BLUE_SIZE, 8,
EGL_GREEN_SIZE, 8,
EGL_RED_SIZE, 8,
EGL_NONE
};
EGLint w, h, format;
EGLint numConfigs;
EGLConfig configs[2];
EGLSurface surface;
EGLContext context;
EGLDisplay display = eglGetDisplay(EGL_DEFAULT_DISPLAY);
eglInitialize(display, 0, 0);
eglGetConfigs(display, configs, 2, &numConfigs);
eglChooseConfig(display, attribs, configs, 2, &numConfigs);
ANativeWindow_setBuffersGeometry(engine->app->window, 0, 0, format);
create_shaders();
surface = eglCreateWindowSurface(display, configs[0], engine->app->window, NULL);
eglBindAPI(EGL_OPENGL_ES_API);
context = eglCreateContext(display, configs[0], NULL, NULL);
if (eglMakeCurrent(display, surface, surface, context) == EGL_FALSE) {
LOGW("Unable to eglMakeCurrent");
return -1;
}
eglSwapInterval(display, 0);
eglQuerySurface(display, surface, EGL_WIDTH, &w);
eglQuerySurface(display, surface, EGL_HEIGHT, &h);
engine->display = display;
engine->context = context;
engine->surface = surface;
engine->width = w;
engine->height = h;
engine->state.angle = 0;
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_FASTEST);
glEnable(GL_CULL_FACE);
glShadeModel(GL_SMOOTH);
glDisable(GL_DEPTH_TEST);
return 0;
}
static void engine_draw_frame(struct engine* engine) {
if (engine->display == NULL) {
return;
}
static double r = 0;
r += 0.01;
glViewport(0, 0, engine->width, engine->height);
glClear(GL_COLOR_BUFFER_BIT);
glClearColor(0.0, 0.0, 0.0, 1.0);
glEnableClientState(GL_VERTEX_ARRAY);
GLfloat vTriangle[] = { 0.0, 0.5, 0.0,
-0.5, -0.5, 0.0,
0.5, -0.5, 0.0 };
GLfloat cTriangle[] = { 0.9, 0.0, 0.0, 1.0 };
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, vTriangle);
glEnableVertexAttribArray(0);
glDrawArrays(GL_TRIANGLES, 0, 3);
eglSwapBuffers(engine->display, engine->surface);
}
static void engine_term_display(struct engine* engine) {
if (engine->display != EGL_NO_DISPLAY) {
eglMakeCurrent(engine->display, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
if (engine->context != EGL_NO_CONTEXT) {
eglDestroyContext(engine->display, engine->context);
}
if (engine->surface != EGL_NO_SURFACE) {
eglDestroySurface(engine->display, engine->surface);
}
eglTerminate(engine->display);
}
engine->animating = 0;
engine->display = EGL_NO_DISPLAY;
engine->context = EGL_NO_CONTEXT;
engine->surface = EGL_NO_SURFACE;
}
static int32_t engine_handle_input(struct android_app* app, AInputEvent* event) {
struct engine* engine = (struct engine*)app->userData;
if (AInputEvent_getType(event) == AINPUT_EVENT_TYPE_MOTION) {
engine->state.x = AMotionEvent_getX(event, 0);
engine->state.y = AMotionEvent_getY(event, 0);
return 1;
}
return 0;
}
static void engine_handle_cmd(struct android_app* app, int32_t cmd) {
struct engine* engine = (struct engine*)app->userData;
switch (cmd) {
case APP_CMD_SAVE_STATE:
engine->app->savedState = malloc(sizeof(struct saved_state));
*((struct saved_state*)engine->app->savedState) = engine->state;
engine->app->savedStateSize = sizeof(struct saved_state);
break;
case APP_CMD_INIT_WINDOW:
if (engine->app->window != NULL) {
engine_init_display(engine);
engine_draw_frame(engine);
}
break;
case APP_CMD_TERM_WINDOW:
engine_term_display(engine);
break;
case APP_CMD_GAINED_FOCUS:
if (engine->accelerometerSensor != NULL) {
ASensorEventQueue_enableSensor(engine->sensorEventQueue,
engine->accelerometerSensor);
ASensorEventQueue_setEventRate(engine->sensorEventQueue,
engine->accelerometerSensor, (1000L / 60) * 1000);
}
break;
case APP_CMD_LOST_FOCUS:
if (engine->accelerometerSensor != NULL) {
ASensorEventQueue_disableSensor(engine->sensorEventQueue,
engine->accelerometerSensor);
}
engine->animating = 0;
engine_draw_frame(engine);
break;
}
}
void android_main(struct android_app* state) {
struct engine engine;
memset(&engine, 0, sizeof(engine));
state->userData = &engine;
state->onAppCmd = engine_handle_cmd;
state->onInputEvent = engine_handle_input;
engine.app = state;
engine.sensorManager = ASensorManager_getInstance();
engine.accelerometerSensor = ASensorManager_getDefaultSensor(engine.sensorManager,
ASENSOR_TYPE_ACCELEROMETER);
engine.sensorEventQueue = ASensorManager_createEventQueue(engine.sensorManager,
state->looper, LOOPER_ID_USER, NULL, NULL);
if (state->savedState != NULL) {
engine.state = *(struct saved_state*)state->savedState;
}
engine.animating = 1;
while (1) {
int ident;
int events;
struct android_poll_source* source;
while ((ident = ALooper_pollAll(engine.animating ? 0 : -1, NULL, &events,
(void**)&source)) >= 0) {
if (source != NULL) {
source->process(state, source);
}
if (ident == LOOPER_ID_USER) {
if (engine.accelerometerSensor != NULL) {
ASensorEvent event;
while (ASensorEventQueue_getEvents(engine.sensorEventQueue,
&event, 1) > 0) {
LOGI("accelerometer: x=%f y=%f z=%f",
event.acceleration.x, event.acceleration.y,
event.acceleration.z);
}
}
}
if (state->destroyRequested != 0) {
engine_term_display(&engine);
return;
}
}
if (engine.animating) {
engine.state.angle += .01f;
if (engine.state.angle > 1) {
engine.state.angle = 0;
}
engine_draw_frame(&engine);
}
}
}