TextureQuadBatcher
由于Unigine没有SpriteBatch类似物,需要手动实现一个。当然用Unigine.Ffp
直接来搞也可以,只不过效率就会差一些了。
因为我打算同时用Myra和ImGui.NET,因此这里偷了个懒,去借用Unigine示例里整合ImGui.NET用的Shader/Material了。不打算用ImGui的可以去把unigine-imgui-csharp-integration-sample\data\imgui.basemat
拷贝到自己项目的data目录下。
接下来按照它这个Shader使用顶点的方式,定义顶点格式(其实就是ImGui的顶点格式):
[StructLayout(LayoutKind.Sequential, Pack = 1)]
struct VertexLayout(VertexPositionColorTexture vertexData)
{public vec2 Position = new(vertexData.Position.X, vertexData.Position.Y);public vec2 TexCoord = new(vertexData.TextureCoordinate.X, vertexData.TextureCoordinate.Y);public uint Color = vertexData.Color.PackedValue;
}
VertexPositionColorTexture
是Myra传递过来的顶点数据格式。
接下来声明几个会用到的常量和变量:
const int MaxSprites = 2048;
const int MaxVertices = MaxSprites * 4;
const int MaxIndices = MaxSprites * 6;readonly MeshDynamic quadMesh;
readonly Material quadMaterial;
Texture? lastTexture;readonly VertexLayout[] vertexData = new VertexLayout[MaxVertices];
int vertexCount;
指定一次最多绘制2048个图元,这个数量已经很多了,再多会导致Mesh的Index尺寸超过65536,效率就会有所降低(Unigine的Index是4字节int)。
MeshDynamic是Unigine的动态Mesh对象,创建并指定顶点格式的过程也很简单:
quadMesh = new MeshDynamic(MeshDynamic.USAGE_DYNAMIC_VERTEX);
var vertexFormat = new MeshDynamic.Attribute[3];
vertexFormat[0].type = MeshDynamic.TYPE_FLOAT;
vertexFormat[0].offset = 0;
vertexFormat[0].size = 2;
vertexFormat[1].type = MeshDynamic.TYPE_FLOAT;
vertexFormat[1].offset = 8;
vertexFormat[1].size = 2;
vertexFormat[2].type = MeshDynamic.TYPE_UCHAR;
vertexFormat[2].offset = 16;
vertexFormat[2].size = 4;
quadMesh.SetVertexFormat(vertexFormat);
注意在创建的时候,指定USAGE_DYNAMIC_VERTEX,而不是USAGE_DYNAMIC_ALL。由于Myra会让我们绘制的全都是单纯的Quad,因此Index可以完全不动,提前创建好就不再更改了:
var indexData = new int[MaxIndices];
for (int i = 0, j = 0; i < MaxIndices; i += 6, j += 4) {indexData[i + 0] = j + 0;indexData[i + 1] = j + 1;indexData[i + 2] = j + 2;indexData[i + 3] = j + 3;indexData[i + 4] = j + 2;indexData[i + 5] = j + 1;
}
quadMesh.SetIndicesArray(indexData);
quadMesh.FlushIndices();
顺便把Material也创建好:
quadMaterial = Materials.FindManualMaterial("imgui").Inherit();
基本的数据都准备好了之后,开始制作绘制Quad的过程。这里先采用和Xna的SpriteBatch类似的Begin/Draw/End结构。首先是Begin:
public void Begin(TextureFiltering textureFiltering)
{//设置渲染状态RenderState.SaveState();RenderState.ClearStates();RenderState.SetBlendFunc(RenderState.BLEND_ONE, RenderState.BLEND_ONE_MINUS_SRC_ALPHA);RenderState.PolygonCull = RenderState.CULL_NONE;RenderState.DepthFunc = RenderState.DEPTH_NONE;//用正交投影矩阵渲染var clientRenderSize = WindowManager.MainWindow.ClientRenderSize;float left = 0;float right = clientRenderSize.x;float top = 0;float bottom = clientRenderSize.y;var orthoProj = new mat4 {m00 = 2.0f / (right - left),m03 = (right + left) / (left - right),m11 = 2.0f / (top - bottom),m13 = (top + bottom) / (bottom - top),m22 = 0.5f,m23 = 0.5f,m33 = 1.0f};Renderer.Projection = orthoProj;//选定为当前渲染的Shadervar shader = quadMaterial.GetShaderForce("imgui");var pass = quadMaterial.GetRenderPass("imgui");Renderer.SetShaderParameters(pass, shader, quadMaterial, false);//选定为当前渲染MeshquadMesh.Bind();
}
一目了然,没什么好说的。要注意的就是RenderState.SetBlendFunc()
这里,是One加上OneMinusSrcAlpha的模式,和传统Alpha混合的SrcAlpha加OneMinusSrcAlpha模式不同。因为Myra使用的是Pre-Multiplied Alpha。
顺便把End也写了:
public void End()
{Flush();//恢复渲染状态quadMesh.Unbind();RenderState.RestoreState();
}
之后是和Myra对接的部分:
public void DrawQuad(Texture texture, ref VertexPositionColorTexture topLeft, ref VertexPositionColorTexture topRight, ref VertexPositionColorTexture bottomLeft, ref VertexPositionColorTexture bottomRight)
{if (texture != lastTexture || vertexCount >= MaxVertices) {Flush();lastTexture = texture;}vertexData[vertexCount++] = new VertexLayout(topLeft);vertexData[vertexCount++] = new VertexLayout(topRight);vertexData[vertexCount++] = new VertexLayout(bottomLeft);vertexData[vertexCount++] = new VertexLayout(bottomRight);
}
其实就是将Myra传递过来的数据缓存起来,当Texture发生了改变,或者顶点数量超过缓冲区上限了之后,再输出。
最后就是最重要的输出部分了,然而这部分反而代码很简单:
public void Flush()
{if (vertexCount == 0 || lastTexture == null) {return;}//应用顶点数据quadMesh.ClearVertex();unsafe {fixed (void* pVertexData = vertexData) {quadMesh.SetVertexArray((nint)pVertexData, vertexCount);}}quadMesh.FlushVertex();//绘制RenderState.SetTexture(RenderState.BIND_FRAGMENT, 0, lastTexture);quadMesh.RenderSurface(MeshDynamic.MODE_TRIANGLES, 0, 0, vertexCount / 4 * 6);//重置计数vertexCount = 0;
}
Unigine提供的SetVertexArray不完整,因此这里多了一块unsafe。
绘制部分没啥好说的:设置纹理,输出三角形,通过vertexCount / 4 * 6
计算得到绘制的Index总数量。
IMyraRenderer
MyraRenderer支持两种模式,Sprite模式:给Xna的SpriteBatch类似物使用。Quad模式:直接绘制顶点。Unigine自然要使用Quad模式:
RendererType IMyraRenderer.RendererType => RendererType.Quad;
之后声明几个后面要用到的变量,并将其初始化:
readonly TextureQuadBatcher quadBatcher = new();Rectangle currentScissor;
bool isBeginCalled;public MyraRenderer()
{var clientRenderSize = WindowManager.MainWindow.ClientRenderSize;currentScissor = new Rectangle(0, 0, clientRenderSize.x, clientRenderSize.y);
}
然后实现Myra的Scissor:
Rectangle IMyraRenderer.Scissor
{get => currentScissor;set {if (value != currentScissor) {Flush();currentScissor = value;var clientRenderSize = WindowManager.MainWindow.ClientRenderSize;int y = clientRenderSize.y - (currentScissor.Y + currentScissor.Height); //ScissorTest是右手坐标系,Y轴从屏幕下方往上数RenderState.SetScissorTest((float)currentScissor.X / clientRenderSize.x, (float)y / clientRenderSize.y, (float)currentScissor.Width / clientRenderSize.x, (float)currentScissor.Height / clientRenderSize.y);}}
}
每次Scissor变化的时候,都要将已有的缓存刷新,再调用RenderState.SetScissorTest
。由于Unigine是右手坐标系,屏幕左下角是(0.0f,0.0f),右上角是(1.0f,1.0f)。而Myra传递过来的是传统的屏幕像素坐标,左上角为(0,0)右下角是(ClientRenderSize.x,ClientRenderSize.y),因此这里要对坐标系进行转换。
剩下的几个接口就很简单了,把相应的参数传给TextureQuadBatcher就可以。
void IMyraRenderer.Begin(TextureFiltering textureFiltering)
{quadBatcher.Begin(textureFiltering);isBeginCalled = true;
}void IMyraRenderer.End()
{quadBatcher.End();isBeginCalled = false;
}void IMyraRenderer.DrawSprite(object texture, Vector2 pos, Rectangle? src, FSColor color, float rotation, Vector2 scale, float depth)
{//ignored
}void IMyraRenderer.DrawQuad(object texture, ref VertexPositionColorTexture topLeft, ref VertexPositionColorTexture topRight, ref VertexPositionColorTexture bottomLeft, ref VertexPositionColorTexture bottomRight)
{quadBatcher.DrawQuad((Texture)texture, ref topLeft, ref topRight, ref bottomLeft, ref bottomRight);
}void Flush()
{if (isBeginCalled) {quadBatcher.Flush();}
}
DrawSprite/DrawQuad二者只需实现其一,前面选择了哪个模式就实现哪个模式即可。
如此一来渲染的部分就实现完成了。这并不是效率最高的实现方式,但概念上最简单。目前先这么做,先让程序跑起来再优化。