I load textures using OpenGL ES, below is my code.
The graphic consists of two textures of the same size, a stop button and a blue glow behind.
The first picture below was made using the iPad simulator in xCode, and the second on the device itself. The first graphic is the correct conclusion when I exported graphics from Illustrator. However, when I downloaded the program on the iPad, it gives me a 2nd chart. It seems that the blue light texture behind the stop button has become smaller. Why is this so?
I can compensate by increasing the texture of the blue light, but that would be wrong, since the way it should look in Illustrator is the first plot.
Here is my code.
// // OpenGLES_Ch3_4ViewController.m // OpenGLES_Ch3_4 // #import "OpenGLES_Ch3_4ViewController.h" #import "AGLKVertexAttribArrayBuffer.h" #import "AGLKContext.h" #define Y_POS 1.0 #define ASPECT_RATIO 0.75f #define SIZE 0.8 @implementation OpenGLES_Ch3_4ViewController @synthesize baseEffect; @synthesize vertexBuffer; @synthesize textureInfo0; @synthesize textureInfo1; ///////////////////////////////////////////////////////////////// // This data type is used to store information for each vertex typedef struct { GLKVector3 positionCoords; GLKVector2 textureCoords; } SceneVertex; ///////////////////////////////////////////////////////////////// // Define vertex data for a triangle to use in example //static const SceneVertex vertices[] = static const SceneVertex vertices[] = { {{-1.0f*SIZE, -ASPECT_RATIO*SIZE, 0.0f}, {0.0f, 0.0f}}, // first triangle {{ 0.0f*SIZE, -ASPECT_RATIO*SIZE, 0.0f}, {1.0f, 0.0f}}, {{-1.0f*SIZE, 0.0f*SIZE, 0.0f}, {0.0f, 1.0f}}, {{ 0.0f*SIZE, -ASPECT_RATIO*SIZE, 0.0f}, {1.0f, 0.0f}}, // second triangle {{-1.0f*SIZE, 0.0f*SIZE, 0.0f}, {0.0f, 1.0f}}, {{ 0.0f*SIZE, 0.0f*SIZE, 0.0f}, {1.0f, 1.0f}}, }; ///////////////////////////////////////////////////////////////// // Called when the view controller view is loaded // Perform initialization before the view is asked to draw - (void)viewDidLoad { [super viewDidLoad]; // Verify the type of view created automatically by the // Interface Builder storyboard GLKView *view = (GLKView *)self.view; NSAssert([view isKindOfClass:[GLKView class]], @"View controller view is not a GLKView"); // Create an OpenGL ES 2.0 context and provide it to the // view view.context = [[AGLKContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2]; // Make the new context current [AGLKContext setCurrentContext:view.context]; // Create a base effect that provides standard OpenGL ES 2.0 // shading language programs and set constants to be used for // all subsequent rendering self.baseEffect = [[GLKBaseEffect alloc] init]; self.baseEffect.useConstantColor = GL_TRUE; self.baseEffect.constantColor = GLKVector4Make( 1.0f, // Red 1.0f, // Green 1.0f, // Blue 1.0f);// Alpha // Set the background color stored in the current context ((AGLKContext *)view.context).clearColor = GLKVector4Make( 0.0f, // Red 0.0f, // Green 0.0f, // Blue 1.0f);// Alpha // Create vertex buffer containing vertices to draw self.vertexBuffer = [[AGLKVertexAttribArrayBuffer alloc] initWithAttribStride:sizeof(SceneVertex) numberOfVertices:sizeof(vertices) / sizeof(SceneVertex) bytes:vertices usage:GL_STATIC_DRAW]; // Setup texture0 CGImageRef imageRef0 = [[UIImage imageNamed:@"stoplight_full.png"] CGImage]; self.textureInfo0 = [GLKTextureLoader textureWithCGImage:imageRef0 options:[NSDictionary dictionaryWithObjectsAndKeys: [NSNumber numberWithBool:YES], GLKTextureLoaderOriginBottomLeft, nil] error:NULL]; self.textureInfo0_2 = [GLKTextureLoader textureWithCGImage:imageRef0 options:nil error:NULL]; // Setup texture1 CGImageRef imageRef1 = [[UIImage imageNamed:@"stop_button.png"] CGImage]; self.textureInfo1 = [GLKTextureLoader textureWithCGImage:imageRef1 options:[NSDictionary dictionaryWithObjectsAndKeys: [NSNumber numberWithBool:YES], GLKTextureLoaderOriginBottomLeft, nil] error:NULL]; self.textureInfo1_2 = [GLKTextureLoader textureWithCGImage:imageRef1 options:nil error:NULL]; // Enable fragment blending with Frame Buffer contents glEnable(GL_BLEND); glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); } ///////////////////////////////////////////////////////////////// // GLKView delegate method: Called by the view controller view // whenever Cocoa Touch asks the view controller view to // draw itself. (In this case, render into a frame buffer that // shares memory with a Core Animation Layer) - (void)glkView:(GLKView *)view drawInRect:(CGRect)rect { // Clear back frame buffer (erase previous drawing) [(AGLKContext *)view.context clear:GL_COLOR_BUFFER_BIT]; [self.vertexBuffer prepareToDrawWithAttrib:GLKVertexAttribPosition numberOfCoordinates:3 attribOffset:offsetof(SceneVertex, positionCoords) shouldEnable:YES]; [self.vertexBuffer prepareToDrawWithAttrib:GLKVertexAttribTexCoord0 numberOfCoordinates:2 attribOffset:offsetof(SceneVertex, textureCoords) shouldEnable:YES]; self.baseEffect.texture2d0.name = self.textureInfo0.name; self.baseEffect.texture2d0.target = self.textureInfo0.target; [self.baseEffect prepareToDraw]; // Draw triangles using the vertices in the // currently bound vertex buffer [self.vertexBuffer drawArrayWithMode:GL_TRIANGLES startVertexIndex:0 numberOfVertices:sizeof(vertices) / sizeof(SceneVertex)]; self.baseEffect.texture2d0.name = self.textureInfo1.name; self.baseEffect.texture2d0.target = self.textureInfo1.target; [self.baseEffect prepareToDraw]; // Draw triangles using currently bound vertex buffer [self.vertexBuffer drawArrayWithMode:GL_TRIANGLES startVertexIndex:0 numberOfVertices:sizeof(vertices) / sizeof(SceneVertex)]; }
