[4.0unstable] Gorilla is not rendered for Vulkan.

przemir · Post by **przemir** » Fri Oct 31, 2025 2:29 am

It works for Direct3D11 and OpenGL, but Vulkan shows nothing (although RenderDoc have some data during Vertex input stage).

OpenGL

Vulkan

RenderDoc (Vulkan)

To make this simpler to test I made sample https://github.com/przemir/Ogre_Sample_Gorilla
similar in style to ogre samples.

VertexShader:

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#version ogre_glsl_ver_330

vulkan_layout( OGRE_DIFFUSE ) in vec4 colour;
vulkan_layout( OGRE_POSITION ) in vec3 vertex;
vulkan_layout( OGRE_TEXCOORD0 ) in vec2 uv0;

out gl_PerVertex
{
    vec4 gl_Position;
};

/*
vulkan_layout( location = 0 ) out vec4 oUv;
vulkan_layout( location = 1 ) out vec4 oColor;
*/

vulkan_layout( location = 0 )
out block
{
    vec4 oUv;
    vec4 oColor;
} outVs;

void main()
{
    outVs.oUv = vec4(uv0, 1.0, 1.0);
    outVs.oColor = colour;
    gl_Position = vec4(vertex, 1.0);
}

PixelShader:

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#version ogre_glsl_ver_330

vulkan_layout( ogre_s0 ) uniform sampler2D atlas;

/*
vulkan_layout( location = 0 ) in vec4 oUv;
vulkan_layout( location = 1 ) in vec4 oColor;
*/

vulkan_layout( location = 0 )
in block
{
    vec4 oUv;
    vec4 oColor;
} inPs;

vulkan_layout( location = 0 )
out vec4 fragColour;

void main()
{
    fragColour = texture(atlas, inPs.oUv.xy) * inPs.oColor;
}

Material

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vertex_program gorilla2DVPHLSL hlsl
{
 	source gorilla2D.hlsl
	entry_point main_vp
	target vs_5_0 vs_4_0 vs_4_0_level_9_1 vs_4_0_level_9_3
} 

fragment_program gorilla2DFPHLSL hlsl
{
	source gorilla2D.hlsl
	entry_point main_fp
	target ps_5_0 ps_4_0 ps_4_0_level_9_1 ps_4_0_level_9_3
}

vertex_program gorilla2DVPGLSL glsl
{
 	source gorilla2DVP.glsl
} 

fragment_program gorilla2DFPGLSL glsl
{
	source gorilla2DFP.glsl
}

vertex_program gorilla2DVPGLSLES glsles
{
 	source gorilla2DVP.glsles
} 

fragment_program gorilla2DFPGLSLES glsles
{
	source gorilla2DFP.glsles
}

vertex_program gorilla2DVPVK glslvk
{
	source gorilla2DVP.glsl
}

fragment_program gorilla2DFPVK glslvk
{
	source gorilla2DFP.glsl
}

// Unified definition
vertex_program gorilla2DVP unified
{
	delegate gorilla2DVPGLSLES
	delegate gorilla2DVPHLSL
	delegate gorilla2DVPGLSL 
	delegate gorilla2DVPVK
}
fragment_program gorilla2DFP unified
{
	delegate gorilla2DFPGLSLES
	delegate gorilla2DFPHLSL
	delegate gorilla2DFPGLSL
	delegate gorilla2DFPVK
}

material Gorilla2D21
{
	technique
	{
		pass
		{
			depth_check off
			depth_write off
			diffuse vertexcolour
			scene_blend alpha_blend

		vertex_program_ref gorilla2DVP
		{
		}

		fragment_program_ref gorilla2DFP
		{
		}
	}
}
}

Prepare render system inside Gorilla:

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void Screen::_prepareRenderSystem(Ogre::v1::RenderOperation &renderOp)
{
        mRenderSystem->_setWorldMatrix(Ogre::Matrix4::IDENTITY);
        mRenderSystem->_setProjectionMatrix(Ogre::Matrix4::IDENTITY);
        mRenderSystem->_setViewMatrix(Ogre::Matrix4::IDENTITY);

    Ogre::TextureGpu* texture = mAtlas->get2DPass()->getTextureUnitState(0)->_getTexturePtr();
    mRenderSystem->_setTexture(0, texture, false);

    Ogre::HlmsManager* hlmsManager = Ogre::Root::getSingleton().getHlmsManager();

    Ogre::HlmsSamplerblock sampler;
    sampler.setAddressingMode(Ogre::TextureAddressingMode::TAM_CLAMP);
    sampler.setFiltering(Ogre::TextureFilterOptions::TFO_TRILINEAR);

    mRenderSystem->_setHlmsSamplerblock(0, hlmsManager->getSamplerblock(sampler));

    // Destroy the last pso created before making a new one.
    if (hasPSO){
        mRenderSystem->_hlmsPipelineStateObjectDestroyed(&pso);
    }

    // Create the PSO for the current render of the GUI
    pso.initialize();
    pso.operationType = Ogre::OT_TRIANGLE_LIST;
    pso.vertexShader = mAtlas->get2DPass()->getVertexProgram();
    pso.pixelShader = mAtlas->get2DPass()->getFragmentProgram();
    pso.macroblock = mAtlas->get2DPass()->getMacroblock();
    pso.blendblock = mAtlas->get2DPass()->getBlendblock();
    pso.vertexElements = renderOp.vertexData->vertexDeclaration->convertToV2(); // Required by DX11 or it will crash! :D

    // Create & Set the PSO to the render system
    mRenderSystem->_hlmsPipelineStateObjectCreated(&pso);
    mRenderSystem->_setPipelineStateObject(&pso);

    // Send the render through. Ogre::v1::CbRenderOp cmd is needed for DX11.
    // A straight renderOperation passed in _render will work in OpenGL.
    Ogre::v1::CbRenderOp cmd = Ogre::v1::CbRenderOp(renderOp);
    mRenderSystem->_setRenderOperation(&cmd);

    hasPSO = true;
}

Gorilla CompositorPass:

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    class GorillaPass : public Ogre::CompositorPass
    {
    public:
        GorillaPass(const Ogre::CompositorPassDef* definition, Ogre::CompositorNode* parentNode, Ogre::Camera* camera, const Ogre::RenderTargetViewDef *rtvDef, Ogre::SceneManager* sceneManager)
            : Ogre::CompositorPass(definition, parentNode)
            , mSceneManager(sceneManager)
            , mCamera(camera)
        {
        }

    virtual void execute(const Ogre::Camera* lodCameraconst)
    {
        profilingBegin();
        Screen* screen = Ogre::any_cast<Screen*>(mCamera->getUserAny());
        screen->renderOnce();
        profilingEnd();
    }

protected:
    Ogre::SceneManager* mSceneManager;
    Ogre::Camera* mCamera;
};

Thanks!

Post by **dark_sylinc** » Yesterday, 2025 4:25 pm

Hi!

There are two problems with this Gorilla implementation that stood out:

Separate shader samplers

In Vulkan we are using separate sampler and texture objects. Therefore gorilla2DFP.glsl needs to be changed into:

Code: Select all

#version ogre_glsl_ver_330

vulkan_layout( ogre_t0 ) uniform texture2D atlas;
vulkan( layout( ogre_s0 ) uniform sampler texSampler );

/*
vulkan_layout( location = 0 ) in vec4 oUv;
vulkan_layout( location = 1 ) in vec4 oColor;
*/

vulkan_layout( location = 0 )
in block
{
    vec4 oUv;
    vec4 oColor;
} inPs;

vulkan_layout( location = 0 )
out vec4 fragColour;

void main()
{
    fragColour = texture(vkSampler2D(atlas, texSampler), inPs.oUv.xy) * inPs.oColor;
}

Incomplete PSO setup

In Gorilla.cpp Screen::_prepareRenderSystem, pso.pass is never setup. This is required. If enabling Vulkan Validation Layers they will complain about the invalid settings right at mRenderSystem->_hlmsPipelineStateObjectCreated(&pso);.

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