Simple iOS glDrawElements - BAD_ACCESS
- by user699215
You can copy paste this into the default OpenGl template created in Xcode.
Why am I not seeing anything :-)
It is strange as the glDrawArrays(GL_TRIANGLES, 0, 3); is working fine, but with
glDrawElements(GL_TRIANGLE_STRIP, sizeof(indices)/sizeof(GLubyte), GL_UNSIGNED_BYTE, indices);
Is giving BAD_ACCESS?
Copy paste this into Xcode default OpenGl template: ViewController
#import "ViewController.h"
#define BUFFER_OFFSET(i) ((char *)NULL + (i))
// Uniform index.
enum
{
UNIFORM_MODELVIEWPROJECTION_MATRIX,
UNIFORM_NORMAL_MATRIX,
NUM_UNIFORMS
};
GLint uniforms[NUM_UNIFORMS];
// Attribute index.
enum
{
ATTRIB_VERTEX,
ATTRIB_NORMAL,
NUM_ATTRIBUTES
};
@interface ViewController () {
GLKMatrix4 _modelViewProjectionMatrix;
GLKMatrix3 _normalMatrix;
float _rotation;
GLuint _vertexArray;
GLuint _vertexBuffer;
NSArray* arrayOfVertex;
}
@property (strong, nonatomic) EAGLContext *context;
@property (strong, nonatomic) GLKBaseEffect *effect;
- (void)setupGL;
- (void)tearDownGL;
@end
@implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
self.context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
GLKView *view = (GLKView *)self.view;
view.context = self.context;
view.drawableDepthFormat = GLKViewDrawableDepthFormat24;
[self setupGL];
}
- (void)dealloc
{
[self tearDownGL];
if ([EAGLContext currentContext] == self.context) {
[EAGLContext setCurrentContext:nil];
}
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
if ([self isViewLoaded] && ([[self view] window] == nil)) {
self.view = nil;
[self tearDownGL];
if ([EAGLContext currentContext] == self.context) {
[EAGLContext setCurrentContext:nil];
}
self.context = nil;
}
// Dispose of any resources that can be recreated.
}
GLuint vertexBufferID;
GLuint indexBufferID;
static const GLfloat vertices[9] = {
-0.5, -0.5, 0.5,
0.5, -0.5, 0.5,
-0.5, 0.5, 0.5
};
static const GLubyte indices[3] = {
0, 1, 2
};
- (void)setupGL
{
[EAGLContext setCurrentContext:self.context];
// [self loadShaders];
self.effect = [[GLKBaseEffect alloc] init];
self.effect.light0.enabled = GL_TRUE;
self.effect.light0.diffuseColor = GLKVector4Make(1.0f, 0.4f, 0.4f, 1.0f);
glEnable(GL_DEPTH_TEST);
// glGenVertexArraysOES(1, &_vertexArray);
// glBindVertexArrayOES(_vertexArray);
glGenBuffers(1, &vertexBufferID);
glBindBuffer(GL_ARRAY_BUFFER, vertexBufferID);
glBufferData(GL_ARRAY_BUFFER,
sizeof(vertices),
vertices,
GL_STATIC_DRAW);
glGenBuffers(1, &indexBufferID);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBufferID);
glBufferData(GL_ELEMENT_ARRAY_BUFFER,
sizeof(indices),
indices,
GL_STATIC_DRAW);
glEnableVertexAttribArray(GLKVertexAttribPosition);
glVertexAttribPointer(GLKVertexAttribPosition, // Specifies the index of the generic vertex attribute to be modified.
3, // Specifies the number of components per generic vertex attribute. Must be 1, 2, 3, 4.
GL_FLOAT, //
GL_FALSE, //
0, //
BUFFER_OFFSET(0)); //
// glBindVertexArrayOES(0);
}
- (void)tearDownGL
{
[EAGLContext setCurrentContext:self.context];
glDeleteBuffers(1, &_vertexBuffer);
glDeleteVertexArraysOES(1, &_vertexArray);
self.effect = nil;
}
#pragma mark - GLKView and GLKViewController delegate methods
- (void)update
{
float aspect = fabsf(self.view.bounds.size.width / self.view.bounds.size.height);
GLKMatrix4 projectionMatrix = GLKMatrix4MakePerspective(GLKMathDegreesToRadians(65.0f), aspect, 0.1f, 100.0f);
self.effect.transform.projectionMatrix = projectionMatrix;
GLKMatrix4 baseModelViewMatrix = GLKMatrix4MakeTranslation(0.0f, 0.0f, -4.0f);
baseModelViewMatrix = GLKMatrix4Rotate(baseModelViewMatrix, _rotation, 0.0f, 1.0f, 0.0f);
// Compute the model view matrix for the object rendered with GLKit
GLKMatrix4 modelViewMatrix = GLKMatrix4MakeTranslation(0.0f, 0.0f, -1.5f);
modelViewMatrix = GLKMatrix4Rotate(modelViewMatrix, _rotation, 1.0f, 1.0f, 1.0f);
modelViewMatrix = GLKMatrix4Multiply(baseModelViewMatrix, modelViewMatrix);
self.effect.transform.modelviewMatrix = modelViewMatrix;
// Compute the model view matrix for the object rendered with ES2
modelViewMatrix = GLKMatrix4MakeTranslation(0.0f, 0.0f, 1.5f);
modelViewMatrix = GLKMatrix4Rotate(modelViewMatrix, _rotation, 1.0f, 1.0f, 1.0f);
modelViewMatrix = GLKMatrix4Multiply(baseModelViewMatrix, modelViewMatrix);
_normalMatrix = GLKMatrix3InvertAndTranspose(GLKMatrix4GetMatrix3(modelViewMatrix), NULL);
_modelViewProjectionMatrix = GLKMatrix4Multiply(projectionMatrix, modelViewMatrix);
_rotation += self.timeSinceLastUpdate * 0.5f;
}
int i;
- (void)glkView:(GLKView *)view drawInRect:(CGRect)rect
{
glClearColor(0.65f, 0.65f, 0.65f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// glBindVertexArrayOES(_vertexArray);
// Render the object with GLKit
[self.effect prepareToDraw];
//glDrawArrays(GL_TRIANGLES, 0, 3);
// Render the object again with ES2
// glDrawArrays(GL_TRIANGLES, 0, 3);
glDrawElements(GL_TRIANGLE_STRIP, sizeof(indices)/sizeof(GLubyte), GL_UNSIGNED_BYTE, indices);
}
@end
