glViewport 在 Android 和 iOS 中的不同结果 [英] glViewport different result in Android and iOS

问题描述

我刚刚开始使用 opengl 为我的跨平台框架(iOS 和 Android)开发渲染器.当我到达视口内容(分屏内容所需)时，注意到 iOS 和 Android 之间存在差异.这是两张图片.

I just got started on a renderer for my cross platform framework (iOS and Android) using opengl es. When I got to the viewport stuff (which is needed for splitscreen stuff) and noticed there is a difference between iOS and Android. Here are two images.

安卓实际上还有另一个故障.它似乎包装了.

Android There is actually another glitch. IT seems to wrap.

iOS

我的问题.两者哪个是正确的?我没有应用任何转换，而是将绘制的四边形带回来一点.glTranslatef(0.0f, 0.0f, -5.f);

My question. Which of the two is correct? I have no transformations applied but one to bring the drawn quad back a bit. glTranslatef(0.0f, 0.0f, -5.f);

初始化代码:

glEnable(GL_TEXTURE_2D);
glShadeModel(GL_SMOOTH);            //Enable Smooth Shading
glClearColor(0.f, 0.f, 0.f, 1.0f);  //Black Background
glClearDepthf(1.0f);                    //Depth Buffer Setup
glEnable(GL_DEPTH_TEST);            //Enables Depth Testing
glDepthFunc(GL_LEQUAL);             //The Type Of Depth Testing To Do

//Really Nice Perspective Calculations
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);

视口和项目代码

glViewport(viewportX, viewportY, viewportW, viewportH);.

glEnable(GL_SCISSOR_TEST);
glScissor(viewportX, viewportY, viewportW, viewportH);

glMatrixMode(GL_PROJECTION);
glLoadIdentity();

... 最后计算截锥体并设置 glFrustrum.我也用过这个代码:

... And finally the frustrum is calculated and set glFrustrum. I have also used this code:

float widthH = width * .1f;
float heightH = height * .1f;
glOrthof(-widthH, widthH, -heightH, heightH, .1f, 100.f);
glScalef(widthH, heightH, 1.f);

也许 Android 或 iOS 有一些默认设置?我一无所知.

Maybe Android or iOS has something set by default? I am clueless.

推荐答案

为有同样问题的人回答我自己的问题.

Answering my own question for those who have the same issue.

我使用 GLKView，它显然在每次渲染调用时调用 glViewport，重置我在前一帧中所做的一切.因此，如果您使用 GLKView，请确保每帧都调用 glViewport！...或滚动您自己的 EAGLView 以获得一些我认为的真正控制权.

I use GLKView which apparently calls the glViewport on each render call, resetting what I just did in the previous frame. So if you use GLKView make sure to call glViewport each frame! ... or roll your own EAGLView to have some real control which I think, I am about to.

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