使用OpenGLES框架在一个简单的iPhone游戏应用程序中工作。 I facing an "EXC Bad Access" error while draw a line on the images。在这里，我将解释你在我的项目中做了什么以及我尝试了什么。
步骤：1我画一个Background Image used GL_TRIANGLE_STRIP。这是我的示例代码，
- (void)viewDidLoad
{
[super viewDidLoad];
self.context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
Test = NO;
Test1 = NO;
if (!self.context)
{
NSLog(@"Failed to create ES context");
}
GLKView *view = (GLKView *)self.view;
view.context = self.context;
[EAGLContext setCurrentContext:self.context];
self.effect = [[GLKBaseEffect alloc] init];
GLKMatrix4 projectionMatrix = GLKMatrix4MakeOrtho(0, 480, 0, 320, -1024, 1024);
self.effect.transform.projectionMatrix = projectionMatrix;
self.player = [[SGGSprite alloc] initWithFile:@"bg.png" effect:self.effect];
self.player.position = GLKVector2Make(self.player.contentSize.width, 460);
self.children = [NSMutableArray array];
[self.children addObject:self.player];
}
- (void)glkView:(GLKView *)view drawInRect:(CGRect)rect
{
// glClearColor(1, 1, 1, 1);
// glClear(GL_COLOR_BUFFER_BIT);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_BLEND);
// Condition satisfied to draw a line code given below, otherwise the background and fish image draw in else part.
if(Test1 == YES)
{
GLKView *view = (GLKView *)self.view;
view.context = self.context;
view.drawableDepthFormat = GLKViewDrawableDepthFormat24;
self.effect = [[GLKBaseEffect alloc] init];
[self.effect prepareToDraw];
const GLfloat line[] =
{
0.0f, 0.5f,
-3.0f,-1.0f,
};
GLuint bufferObjectNameArray;
glGenBuffers(1, &bufferObjectNameArray);
glBindBuffer(GL_ARRAY_BUFFER, bufferObjectNameArray);
glBufferData(
GL_ARRAY_BUFFER, // the target buffer
sizeof(line), // the number of bytes to put into the buffer
line, // a pointer to the data being copied
GL_STATIC_DRAW); // the usage pattern of the data
glEnableVertexAttribArray(GLKVertexAttribPosition);
glVertexAttribPointer(
GLKVertexAttribPosition,
2, // number of coordinates per vertex
GL_FLOAT, // the data type of each component
GL_FALSE, // can the data be scaled
2*4,
NULL);
glDrawArrays(GL_LINES, 0, 2);
}
else
{
//SGGSprite is another class and self.children is mutable array.
for (SGGSprite * sprite in self.children)
{
[sprite render];
}
}
}
//render method in SGGSprite class to draw a fish and background image
- (void)render
{
self.effect.texture2d0.name = self.textureInfo.name;
self.effect.texture2d0.enabled = YES;
self.effect.transform.modelviewMatrix = self.modelMatrix;
[self.effect prepareToDraw];
long offset = (long)&_quad;
glEnableVertexAttribArray(GLKVertexAttribPosition);
glEnableVertexAttribArray(GLKVertexAttribTexCoord0);
NSLog(@"TexturedVertex:%ld",offset);
glVertexAttribPointer(GLKVertexAttribPosition, 2, GL_FLOAT, GL_FALSE, sizeof(TexturedVertex), (void *) (offset + offsetof(TexturedVertex, geometryVertex)));
glVertexAttribPointer(GLKVertexAttribTexCoord0, 2, GL_FLOAT, GL_FALSE, sizeof(TexturedVertex), (void *) (offset + offsetof(TexturedVertex, textureVertex)));
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
}
步骤：2为我的视图绘制背景图像后，我将转到draw a fish images in the screen by using GL_TRIANGLE_STRIP。鱼的图像总是在移动。这是我的示例代码，
（无效）更新 { if（Test == NO） { self.timeSinceLastSpawn + = self.timeSinceLastUpdate; if（self.timeSinceLastSpawn＆gt; 2.0） { self.timeSinceLastSpawn = 0; [自我目标]; //添加鱼图像 }
for (SGGSprite * sprite in self.children)
{
[sprite update:self.timeSinceLastUpdate];
}
}
}
（无效）目标 { SGGSprite * target = [[SGGSprite alloc] initWithFile：@“img2.png”effect：self.effect]; [self.children addObject：target]; //在NSMutable数组中添加鱼图像
int minY = target.contentSize.height / 2; int maxY = 320 - target.contentSize.height / 2; int rangeY = maxY - minY; int actualY =（arc4random（）％rangeY）+ minY;
if（actualY＆lt; = 100） { actualY = 215; }
target.position = GLKVector2Make（480 +（target.contentSize.width），actualY）;
int minVelocity = 480.0 / 12.0;
int maxVelocity = 480.0 / 6.0;
int rangeVelocity = maxVelocity - minVelocity;
int actualVelocity =（arc4random（）％rangeVelocity）+ minVelocity;
target.moveVelocity = GLKVector2Make（-actualVelocity，0）;
}
（void）glkView：（GLKView *）view drawInRect：（CGRect）rect { // glClearColor（1,1,1,1）; // glClear（GL_COLOR_BUFFER_BIT）; glBlendFunc（GL_SRC_ALPHA，GL_ONE_MINUS_SRC_ALPHA）; glEnable（GL_BLEND）;
//条件满足绘制下面给出的行代码，否则背景和鱼图像绘制在else部分。 if（Test1 == YES） { GLKView * view =（GLKView *）self.view; view.context = self.context; view.drawableDepthFormat = GLKViewDrawableDepthFormat24;
self.effect = [[GLKBaseEffect alloc] init];
[self.effect prepareToDraw];
const GLfloat line[] =
{
0.0f, 0.5f,
-3.0f,-1.0f,
};
GLuint bufferObjectNameArray;
glGenBuffers(1, &bufferObjectNameArray);
glBindBuffer(GL_ARRAY_BUFFER, bufferObjectNameArray);
glBufferData(
GL_ARRAY_BUFFER, // the target buffer
sizeof(line), // the number of bytes to put into the buffer
line, // a pointer to the data being copied
GL_STATIC_DRAW); // the usage pattern of the data
glEnableVertexAttribArray(GLKVertexAttribPosition);
glVertexAttribPointer(
GLKVertexAttribPosition,
2, // number of coordinates per vertex
GL_FLOAT, // the data type of each component
GL_FALSE, // can the data be scaled
2*4,
NULL);
glDrawArrays(GL_LINES, 0, 2);
}
else
{
//SGGSprite is another class and self.children is mutable array.
for (SGGSprite * sprite in self.children)
{
[sprite render];
}
}
}
步骤：3现在我在屏幕上绘制背景图像和鱼图像。它完美无缺。现在我在鱼图像和背景图像上方的屏幕中to draw a white line (using GL_LINE)。当我使用下面的代码绘制一条线时，
- （void）touchesBegan：（NSSet *）触及withEvent：（UIEvent *）事件 { 测试=是; Test1 = YES; }
- (void)update
{
if(Test == NO)
{
self.timeSinceLastSpawn += self.timeSinceLastUpdate;
NSLog(@"timeSinceLastUpdate:%f",self.timeSinceLastUpdate);
if (self.timeSinceLastSpawn > 2.0)
{
self.timeSinceLastSpawn = 0;
[self target];
}
NSLog(@"Children count:%d",[self.children count]);
for (SGGSprite * sprite in self.children)
{
[sprite update:self.timeSinceLastUpdate];
}
}
}
- (void)glkView:(GLKView *)view drawInRect:(CGRect)rect
{
// glClearColor(1, 1, 1, 1);
// glClear(GL_COLOR_BUFFER_BIT);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_BLEND);
// Condition satisfied to draw a line code given below, otherwise the background and fish image draw in else part.
if(Test1 == YES)
{
GLKView *view = (GLKView *)self.view;
view.context = self.context;
view.drawableDepthFormat = GLKViewDrawableDepthFormat24;
self.effect = [[GLKBaseEffect alloc] init];
[self.effect prepareToDraw];
const GLfloat line[] =
{
0.0f, 0.5f,
-3.0f,-1.0f,
};
GLuint bufferObjectNameArray;
glGenBuffers(1, &bufferObjectNameArray);
glBindBuffer(GL_ARRAY_BUFFER, bufferObjectNameArray);
glBufferData(
GL_ARRAY_BUFFER, // the target buffer
sizeof(line), // the number of bytes to put into the buffer
line, // a pointer to the data being copied
GL_STATIC_DRAW); // the usage pattern of the data
glEnableVertexAttribArray(GLKVertexAttribPosition);
glVertexAttribPointer(
GLKVertexAttribPosition,
2, // number of coordinates per vertex
GL_FLOAT, // the data type of each component
GL_FALSE, // can the data be scaled
2*4,
NULL);
glDrawArrays(GL_LINES, 0, 2);
}
else
{
//SGGSprite is another class and self.children is mutable array, Draw a fish and background image
for (SGGSprite * sprite in self.children)
{
[sprite render];
}
}
}
应用程序在“glDrawArrays（GL_TRIANGLE_STRIP，0,4）”行中崩溃; //当我触摸屏幕时，错误发生在这里 - >
（无效）呈现 { self.effect.texture2d0.name = self.textureInfo.name; self.effect.texture2d0.enabled = YES; self.effect.transform.modelviewMatrix = self.modelMatrix;
[self.effect prepareToDraw];
long offset = (long)&_quad;
glEnableVertexAttribArray(GLKVertexAttribPosition);
glEnableVertexAttribArray(GLKVertexAttribTexCoord0);
NSLog(@"TexturedVertex:%ld",offset);
glVertexAttribPointer(GLKVertexAttribPosition, 2, GL_FLOAT, GL_FALSE, sizeof(TexturedVertex), (void *) (offset + offsetof(TexturedVertex, geometryVertex)));
glVertexAttribPointer(GLKVertexAttribTexCoord0, 2, GL_FLOAT, GL_FALSE, sizeof(TexturedVertex), (void *) (offset + offsetof(TexturedVertex, textureVertex)));
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); // ERROR comes from this line, when i touch the screen.
}
您能否请参考这些代码并告诉我的代码有什么问题？我该怎么做才能解决这个问题？请帮我。提前致谢。