Objective c 指针和opengl绘图的问题
我正在尝试实现一个简单的rendermanager。另一个类提供了表示四边形的结构,该结构将复制到rendermanager中的顶点数组缓冲区中 然而,复制似乎不起作用,当我手动创建一个结构并复制到vertexarray中时,一切都很好,并且呈现出来。但在副本的某个地方,一切都出错了。我可以用GDB看到这一点,值是不同的,但我无法弄清楚到底发生了什么 RenderManager方法 如果我把这句话说出来,什么都不会吸引人。使用它,我得到了我期待的漂亮的四元 给出结果Objective c 指针和opengl绘图的问题,objective-c,c,pointers,opengl-es,Objective C,C,Pointers,Opengl Es,我正在尝试实现一个简单的rendermanager。另一个类提供了表示四边形的结构,该结构将复制到rendermanager中的顶点数组缓冲区中 然而,复制似乎不起作用,当我手动创建一个结构并复制到vertexarray中时,一切都很好,并且呈现出来。但在副本的某个地方,一切都出错了。我可以用GDB看到这一点,值是不同的,但我无法弄清楚到底发生了什么 RenderManager方法 如果我把这句话说出来,什么都不会吸引人。使用它,我得到了我期待的漂亮的四元 给出结果 2011-10-21 21:
2011-10-21 21:29:21.456 TerrainRendering[11293:fb03] Tiles:7316200 Disgusting pointer math:7316200
2011-10-21 21:29:21.458 TerrainRendering[11293:fb03] Tiles:7316200 Disgusting pointer math:73162f0
2011-10-21 21:29:21.463 TerrainRendering[11293:fb03] Tiles:7316200 Disgusting pointer math:73163e0
2011-10-21 21:29:21.464 TerrainRendering[11293:fb03] Tiles:7316200 Disgusting pointer math:73164d0
2011-10-21 21:29:21.465 TerrainRendering[11293:fb03] Tiles:7316200 Disgusting pointer math:73165c0
2011-10-21 21:29:21.465 TerrainRendering[11293:fb03] Tiles:7316200 Disgusting pointer math:7316200
2011-10-21 21:29:21.466 TerrainRendering[11293:fb03] Tiles:7316200 Disgusting pointer math:73164d0
2011-10-21 21:29:21.467 TerrainRendering[11293:fb03] Tiles:7316200 Disgusting pointer math:73167a0
2011-10-21 21:29:21.470 TerrainRendering[11293:fb03] Tiles:7316200 Disgusting pointer math:7316a70
2011-10-21 21:29:21.470 TerrainRendering[11293:fb03] Tiles:7316200 Disgusting pointer math:7316d40
memcpy中的偏移量应为i*MAX_HEIGHT+j。您希望使用iouter循环跳转行,并使用j inner循环按顺序深入研究它们
希望这有帮助您在memcpy中的偏移量应该是i*MAX\u HEIGHT+j。您希望使用iouter循环跳转行,并使用j inner循环按顺序深入研究它们
希望这有帮助NsLog@%x%x。。。tiles和quad*tiles+i*j+j的地址,我认为计算出的地址不是您期望的地址。现在,指针值是您期望的吗?或者应该是什么?老实说,我真的不确定我在期待什么。但似乎不正确。NsLog@%x%x。。。tiles和quad*tiles+i*j+j的地址,我认为计算出的地址不是您期望的地址。现在,指针值是您期望的吗?或者应该是什么?老实说,我真的不确定我在期待什么。但这似乎并不正确。
memcpy(iva, &draw, sizeof(draw));
. . . OpenGl methods
//Add the quad details to the render queue
-(void)addDetailsToRenderQueue:(quad *)details
{
if(iva == NULL)
NSLog(@"Error claiming memory, something is very wrong");
if(renderCount + 1 > MAX_QUADS){
NSLog(@"Render buffer full, dumping...");
[self render];
}
memcpy((quad *)iva + renderCount++, &details, sizeof(quad));
}
//Render the details in the render queue, for each quad we need to make two triangles.
-(void)render
{
int counter = 0;
renderCount *= 5;
for(int i;i < renderCount;){
ivaIndices[counter++] = i + 0; // Bottom left
ivaIndices[counter++] = i + 1; //Top Left
ivaIndices[counter++] = i + 4; //Center
ivaIndices[counter++] = i + 1; //Top Left
ivaIndices[counter++] = i + 2; //Top right
ivaIndices[counter++] = i + 4; //Center
ivaIndices[counter++] = i + 2; //Top right
ivaIndices[counter++] = i + 3; //Bottom right
ivaIndices[counter++] = i + 4; //Center
ivaIndices[counter++] = i + 3; //Bottom right
ivaIndices[counter++] = i + 0; //Bottom Left
ivaIndices[counter++] = i + 4; //Center
i += 5;
}
glBindVertexArrayOES(_vertexArray);
glDrawElements(GL_LINE_STRIP,12, GL_UNSIGNED_SHORT, ivaIndices);
// Reset the number of quads which need to be rendered
renderCount = 0;
}
@interface TileSet : NSObject
{
quad *tiles;
NSUInteger tileCount;
RenderManager *sharedRenderManager;
}
-(id)init
{
if([super init]){
tiles = calloc(MAX_HEIGHT * MAX_WIDTH, sizeof(quad));
tileCount = 0;
sharedRenderManager = [RenderManager sharedManager];
}
[self fillArray];
return self;
}
-(void)fillArray
{
int rows = 4;
int columns = 12;
for(int i = 0; i < rows;i += 2) {
for(int j = 0;j < columns;j += 2) {
quad tmp;
tmp.v1.x = i;
tmp.v1.y = j;
tmp.v1.z = 0.0f;
tmp.v1.nx = 0.0f;
tmp.v1.ny = 0.0f;
tmp.v1.nz = 1.0f;
tmp.v2.x = i + 1;
tmp.v2.y = j;
tmp.v2.z = 0.0f;
tmp.v2.nx = 0.0f;
tmp.v2.ny = 0.0f;
tmp.v2.nz = 1.0f;
tmp.v3.x = i;
tmp.v3.y = j+1;
tmp.v3.z = 0.0f;
tmp.v3.nx = 0.0f;
tmp.v3.ny = 0.0f;
tmp.v3.nz = 1.0f;
tmp.v4.x = i + 1;
tmp.v4.y = j+1;
tmp.v4.z = 0.0f;
tmp.v4.nx = 0.0f;
tmp.v4.ny = 0.0f;
tmp.v4.nz = 1.0f;
tmp.v5.x = i + 0.5;
tmp.v5.y = j + 0.5;
tmp.v5.z = 0.0f;
tmp.v5.nx = 0.0f;
tmp.v5.ny = 0.0f;
tmp.v5.nz = 1.0f;
memcpy((quad *)tiles + (i*j + j), &tmp, sizeof(quad));
tileCount++;
}
}
}
//Draw the tiles in the tileset, loop through and add to renderManagers queue
-(void)render
{
for(int i = 0; i < tileCount;i++)
[sharedRenderManager addDetailsToRenderQueue:&tiles[0]];
}
NSLog(@"Tiles:%x\tDisgusting pointer math:%x",tiles,(quad *)tiles + (i*j + j));
2011-10-21 21:29:21.456 TerrainRendering[11293:fb03] Tiles:7316200 Disgusting pointer math:7316200
2011-10-21 21:29:21.458 TerrainRendering[11293:fb03] Tiles:7316200 Disgusting pointer math:73162f0
2011-10-21 21:29:21.463 TerrainRendering[11293:fb03] Tiles:7316200 Disgusting pointer math:73163e0
2011-10-21 21:29:21.464 TerrainRendering[11293:fb03] Tiles:7316200 Disgusting pointer math:73164d0
2011-10-21 21:29:21.465 TerrainRendering[11293:fb03] Tiles:7316200 Disgusting pointer math:73165c0
2011-10-21 21:29:21.465 TerrainRendering[11293:fb03] Tiles:7316200 Disgusting pointer math:7316200
2011-10-21 21:29:21.466 TerrainRendering[11293:fb03] Tiles:7316200 Disgusting pointer math:73164d0
2011-10-21 21:29:21.467 TerrainRendering[11293:fb03] Tiles:7316200 Disgusting pointer math:73167a0
2011-10-21 21:29:21.470 TerrainRendering[11293:fb03] Tiles:7316200 Disgusting pointer math:7316a70
2011-10-21 21:29:21.470 TerrainRendering[11293:fb03] Tiles:7316200 Disgusting pointer math:7316d40