I am using Blender to create a 3D cow and obtain the correct vertices (optimized afterwards to remove duplicates). I have created a Cow Class to be able to draw multiple instances of this cow on screen.
我使用Blender创建了一个3D牛，并获得了正确的顶点(经过优化后删除了副本)。我创建了一个Cow类，以便能够在屏幕上绘制这个Cow的多个实例。
Cow 1 is drawn at (-2,0,-10) and Cow 2 is drawn at (2,0,-10). When I render cow 1 only I see Cow 1 at (-2,0,-10). When I render either both cows or only cow 2 (comment render cow 1 out), I only get cow 2 (do not see cow 1) at (2,0,-10). I am making a game where I will have many enemies running around and I need to be able to draw multiple instances of these objects and render them independently at different locations. Can anyone tell me what I am doing wrong? Thanks
牛1被画在(-2,0，-10)和牛2被画在(2,0，-10)。当我渲染奶牛1时，我只看到奶牛1在(-2,0，-10)处。当我同时渲染奶牛或只渲染奶牛2(注释渲染奶牛1)时，我只得到奶牛2(不看到奶牛1)在(2,0，-10)处。我正在制作一个游戏，在这个游戏中，我将会有很多敌人在我周围奔跑，我需要能够绘制这些对象的多个实例，并在不同的位置独立地呈现它们。有人能告诉我我做错了什么吗?谢谢
//
// Cow.m
//
#import "Cow.h"
#import "cow_verts.h"
@implementation Cow
- (id)initWithContext:(EAGLContext *)aContext {
context = aContext;
effect = [[GLKBaseEffect alloc] init];
[EAGLContext setCurrentContext:context];
sharedResourceManager = [ResourceManager sharedResourceManager];
UIImage *textureImage = [UIImage imageNamed:@"cowUV.png"];
texture = [sharedResourceManager addTexture:textureImage];
position = GLKVector3Make(0,0,0);
rotation = GLKVector3Make(0,0,0);
scale = GLKVector3Make(1,1,1);
[self setupGL];
return self;
}
- (void)setupGL {
glGenVertexArraysOES(1, &_vao);
glBindVertexArrayOES(_vao);
glGenBuffers(1, &_dynamicVBO);
glBindBuffer(GL_ARRAY_BUFFER, _dynamicVBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(CowDynamicVertexData), CowDynamicVertexData, GL_DYNAMIC_DRAW);
glVertexAttribPointer(GLKVertexAttribPosition, 3, GL_FLOAT, GL_FALSE, sizeof(dynamicVertexData), (void *)offsetof(dynamicVertexData, position));
glEnableVertexAttribArray(GLKVertexAttribPosition);
glGenBuffers(1, &_staticVBO);
glBindBuffer(GL_ARRAY_BUFFER, _staticVBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(CowStaticVertexData), CowStaticVertexData, GL_STATIC_DRAW);
glVertexAttribPointer(GLKVertexAttribTexCoord0, 2, GL_FLOAT, GL_FALSE, sizeof(staticVertexData), (void *)offsetof(staticVertexData, texCoord));
glEnableVertexAttribArray(GLKVertexAttribTexCoord0);
glGenBuffers(1, &_indexBuffer);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _indexBuffer);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(CowIndices), CowIndices, GL_STATIC_DRAW);
glBindVertexArrayOES(0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
}
- (void)updateWithDelta:(float)aDelta {
float aspect = fabsf([[UIScreen mainScreen] bounds].size.width/ [[UIScreen mainScreen] bounds].size.height);
GLKMatrix4 projectionMatrix = GLKMatrix4MakePerspective(GLKMathDegreesToRadians(65.0f), aspect, 4.0f, 20.0f);
effect.transform.projectionMatrix = projectionMatrix;
rotation.y += 90 * aDelta;
}
- (void)render {
[EAGLContext setCurrentContext:context];
glClearColor(0, 1, 1, 1);
glClear( GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
GLKMatrix4 xRotationMatrix = GLKMatrix4MakeXRotation(GLKMathDegreesToRadians(rotation.x));
GLKMatrix4 yRotationMatrix = GLKMatrix4MakeYRotation(GLKMathDegreesToRadians(rotation.y));
GLKMatrix4 zRotationMatrix = GLKMatrix4MakeZRotation(GLKMathDegreesToRadians(rotation.z));
GLKMatrix4 scaleMatrix = GLKMatrix4MakeScale(scale.x, scale.y, scale.z);
GLKMatrix4 translateMatrix = GLKMatrix4MakeTranslation(position.x, position.y, position.z);
GLKMatrix4 modelMatrix = GLKMatrix4Multiply(translateMatrix,
GLKMatrix4Multiply(scaleMatrix,
GLKMatrix4Multiply(zRotationMatrix,
GLKMatrix4Multiply(yRotationMatrix,
xRotationMatrix))));
effect.transform.modelviewMatrix = modelMatrix;
//GLKMatrix4 viewMatrix = GLKMatrix4MakeLookAt(0, 0, 3, 0, 0, 0, 0, 1, 0);
//effect.transform.modelviewMatrix = GLKMatrix4Multiply(viewMatrix, modelMatrix);
effect.texture2d0.name = texture.name;
effect.texture2d0.target = texture.target;
effect.texture2d0.envMode = GLKTextureEnvModeReplace;
glEnable(GL_DEPTH_TEST);
glEnable(GL_CULL_FACE);
glCullFace(GL_FRONT);
glBindVertexArrayOES(_vao);
[effect prepareToDraw];
glDrawElements(GL_TRIANGLES, sizeof(CowIndices)/sizeof(CowIndices[0]), GL_UNSIGNED_INT, (void *)0);
glBindVertexArrayOES(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
glDisable(GL_DEPTH_TEST);
glDisable(GL_CULL_FACE);
}
@end
//
// Cow.h
//
@interface Cow : NSObject {
EAGLContext *context;
GLuint _vao;
GLuint _staticVBO;
GLuint _dynamicVBO;
GLuint _indexBuffer;
GLKTextureInfo *texture;
GLKBaseEffect *effect;
GLKVector3 position;
GLKVector3 rotation;
GLKVector3 scale;
ResourceManager *sharedResourceManager;
}
- (id)initWithContext:(EAGLContext *)aContext;
- (void)updateWithDelta:(float)aDelta;
- (void)render;
@end
//
// Scene which creates these objects and calls the functions
//
#import "Cow.h"
@implementation GameScene {
NSMutableArray *cows;
}
- (id)init {
if(self = [super init]) {
sharedDirector = [Director sharedDirector];
[EAGLContext setCurrentContext:[sharedDirector context]];
cows = [[NSMutableArray alloc] init];
AbstractEnemy *cow1 = [[Cow alloc] initWithContext:[sharedDirector context]];
cow1.position = GLKVector3Make(-2, 0, -10);
[cows addObject:cow1];
AbstractEnemy *cow2 = [[Cow alloc] initWithContext:[sharedDirector context]];
cow2.position = GLKVector3Make(2, 0, -10);
[cows addObject:cow2];
AbstractEnemy *cow3 = [[Cow alloc] initWithContext:[sharedDirector context]];
cow3.position = GLKVector3Make(0, 0, -15);
[cows addObject:cow3];
}
return self;
}
- (void)updateWithDelta:(GLfloat)aDelta {
for (int i = 0; i < cows.count; i++)
{
[cows[i] updateWithDelta:aDelta];
}
}
- (void)render {
for (int i = 0; i < cows.count; i++)
{
[cows[i] render];
}
}
@end
1 个解决方案
#1
3
From the code you gave, you are calling a glClear() every time before you draw the cow. With all those clear calls, only the last cow you draw will be visible.
根据您给出的代码，每次绘制奶牛之前，您都要调用glClear()。所有这些清晰的呼唤，只有你画的最后一头奶牛是可见的。
Move this call into the scene's render function so you only clear the scene once at the start of each frame.
将此调用移动到场景的渲染函数中，因此您只能在每一帧的开始清除一次场景。
#1
3
From the code you gave, you are calling a glClear() every time before you draw the cow. With all those clear calls, only the last cow you draw will be visible.
根据您给出的代码，每次绘制奶牛之前，您都要调用glClear()。所有这些清晰的呼唤，只有你画的最后一头奶牛是可见的。
Move this call into the scene's render function so you only clear the scene once at the start of each frame.
将此调用移动到场景的渲染函数中，因此您只能在每一帧的开始清除一次场景。