I'm working on converting an existing isometric, orthographically-rendered game over to Horde3D. The existing engine uses pre-rendered sprites with anti-aliased edges, requiring an alpha blend against the background to draw correctly. The pipeline I am using consists so far of two steps: one step draws meshes with material class "Ground" and the next step draws meshes with material class "Wall".
Code:
<!-- Iso Pipeline -->
<Pipeline>
<CommandQueue>
<Stage id="Geometry">
<ClearTarget depthBuf="true" colBuf0="true" />
<DrawGeometry context="SOLID" class="Ground" />
<DrawGeometry context="TRANSLUCENT" class="Wall" order="BACK_TO_FRONT" />
</Stage>
</CommandQueue>
</Pipeline>
<Pipeline>
<CommandQueue>
<Stage id="Geometry">
<ClearTarget depthBuf="true" colBuf0="true" />
<DrawGeometry context="SOLID" class="Ground" />
<DrawGeometry context="TRANSLUCENT" class="Wall" order="BACK_TO_FRONT" />
</Stage>
</CommandQueue>
</Pipeline>
The shader used is very simple as well:
Code:
[[FX]]
sampler2D albedoMap = sampler_state
{
Address=Clamp;
};
context SOLID
{
VertexShader = compile GLSL VS_GENERAL;
PixelShader = compile GLSL FS_GENERAL;
}
context TRANSLUCENT
{
VertexShader = compile GLSL VS_GENERAL;
PixelShader = compile GLSL FS_GENERAL;
BlendMode = Blend;
}
[[VS_GENERAL]]
#include "shaders/utilityLib/vertCommon.glsl"
uniform mat4 viewProjMat;
uniform vec3 viewerPos;
attribute vec3 vertPos;
attribute vec2 texCoords0;
varying vec4 pos, vsPos;
varying vec2 texCoords;
void main(void)
{
pos = calcWorldPos( vec4( vertPos, 1.0 ) );
texCoords = vec2( texCoords0.s, 1.0-texCoords0.t );
gl_Position = viewProjMat * pos;
}
[[FS_GENERAL]]
uniform sampler2D albedoMap;
varying vec4 pos, vsPos;
varying vec2 texCoords;
void main(void)
{
gl_FragColor = texture2D(albedoMap, texCoords);
}
sampler2D albedoMap = sampler_state
{
Address=Clamp;
};
context SOLID
{
VertexShader = compile GLSL VS_GENERAL;
PixelShader = compile GLSL FS_GENERAL;
}
context TRANSLUCENT
{
VertexShader = compile GLSL VS_GENERAL;
PixelShader = compile GLSL FS_GENERAL;
BlendMode = Blend;
}
[[VS_GENERAL]]
#include "shaders/utilityLib/vertCommon.glsl"
uniform mat4 viewProjMat;
uniform vec3 viewerPos;
attribute vec3 vertPos;
attribute vec2 texCoords0;
varying vec4 pos, vsPos;
varying vec2 texCoords;
void main(void)
{
pos = calcWorldPos( vec4( vertPos, 1.0 ) );
texCoords = vec2( texCoords0.s, 1.0-texCoords0.t );
gl_Position = viewProjMat * pos;
}
[[FS_GENERAL]]
uniform sampler2D albedoMap;
varying vec4 pos, vsPos;
varying vec2 texCoords;
void main(void)
{
gl_FragColor = texture2D(albedoMap, texCoords);
}
The various wall pieces are rigidly-cell based; that is, they are derived from the sides of a unit-sized cube, instanced, and transformed into place in a grid pattern. The camera is a basic isometric (rather, dimetric) camera: 30-degree azimuth, 45-degree around Y axis, orthographic projection. It seems straightforward enough, and is a variant of what I have gotten to work in other 3D engines before. However, I'm having the issue that it doesn't actually seem to be sorting the meshes back-to-front. As evidenced by:
(closeup)
You can clearly see halos, where the front wall pieces are drawn before pieces behind them, leaving behind depth in the zbuffer that prevents the back piece pixels from being drawn. Am I misunderstanding the use of the order attribute of DrawGeometry in the pipeline definition? Is there some other way I should be sorting these primitives instead?
Thanks,
Josh
