Question

Just need to figure out a way, using Pixel Shader, to project a texture to an arbitary user-defined quadrilateral.

Will be accepting coordinates of the four sides of a quadrilateral:

/// <defaultValue>0,0</defaultValue>
float2 TopLeft : register(c0);

/// <defaultValue>1,0</defaultValue>
float2 TopRight : register(c1);

/// <defaultValue>0,1</defaultValue>
float2 BottomLeft : register(c2);

/// <defaultValue>1,1</defaultValue>
float2 BottomRight : register(c3);

Tried couple of interpolation algorithm, but couldn t manage to get it right.

是否有你认为我能加以修改以取得预期结果的样本?

Answer 1

这里的问题是,所有现代的3D图形硬件均分三角,而不是四边。因此,如果你要求直接3D或开放的GL提供4个,那么,在内部,APIC将把这4个单元分成两块三角体。这通常不是一个问题,因为所有现代成因都是看上去的,因此,观众不应能够讲述一个四到两个三角的区别,即污染将是无缝的。

The correct way to ask the API to perform this interpolation is to pass it the texture coordinates as per-vertex data, which the API/hardware will interpolate across each pixel. Your pixel shader will then have access to this per-pixel texture coordinate. I assume that when you use the term project you mean simply mapping a rectangular texture onto a quad, and you are not referring to texture projection (which is like a spotlight shining a texture onto surfaces).

The bottom line here is that passing the quad s texture coordinates to the pixel shader is the wrong approach (unless you have some special reason why this is required).

Answer 2

The s a nice paper here描述了你的备选办法(或。基本上,你们需要界定整个四级中的一些精子坐标,然后将碎块价值作为特定垂直价值中的BCP-加权。

索里,不知道任何法典;缺乏对以现代三角关系为主的HW(见真空星69的回答)标语的直接支持,就意味着他们ve倒。

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