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• ### Similar Content

• By elect
Hi,
ok, so, we are having problems with our current mirror reflection implementation.
At the moment we are doing it very simple, so for the i-th frame, we calculate the reflection vectors given the viewPoint and some predefined points on the mirror surface (position and normal).
Then, using the least squared algorithm, we find the point that has the minimum distance from all these reflections vectors. This is going to be our virtual viewPoint (with the right orientation).
After that, we render offscreen to a texture by setting the OpenGL camera on the virtual viewPoint.
And finally we use the rendered texture on the mirror surface.
So far this has always been fine, but now we are having some more strong constraints on accuracy.
What are our best options given that:
- we have a dynamic scene, the mirror and parts of the scene can change continuously from frame to frame
- we have about 3k points (with normals) per mirror, calculated offline using some cad program (such as Catia)
- all the mirror are always perfectly spherical (with different radius vertically and horizontally) and they are always convex
- a scene can have up to 10 mirror
- it should be fast enough also for vr (Htc Vive) on fastest gpus (only desktops)

Looking around, some papers talk about calculating some caustic surface derivation offline, but I don't know if this suits my case
Also, another paper, used some acceleration structures to detect the intersection between the reflection vectors and the scene, and then adjust the corresponding texture coordinate. This looks the most accurate but also very heavy from a computational point of view.

Other than that, I couldn't find anything updated/exhaustive around, can you help me?

• Hello all,
I am currently working on a game engine for use with my game development that I would like to be as flexible as possible.  As such the exact requirements for how things should work can't be nailed down to a specific implementation and I am looking for, at least now, a default good average case scenario design.
Here is what I have implemented:
Deferred rendering using OpenGL Arbitrary number of lights and shadow mapping Each rendered object, as defined by a set of geometry, textures, animation data, and a model matrix is rendered with its own draw call Skeletal animations implemented on the GPU.   Model matrix transformation implemented on the GPU Frustum and octree culling for optimization Here are my questions and concerns:
Doing the skeletal animation on the GPU, currently, requires doing the skinning for each object multiple times per frame: once for the initial geometry rendering and once for the shadow map rendering for each light for which it is not culled.  This seems very inefficient.  Is there a way to do skeletal animation on the GPU only once across these render calls? Without doing the model matrix transformation on the CPU, I fail to see how I can easily batch objects with the same textures and shaders in a single draw call without passing a ton of matrix data to the GPU (an array of model matrices then an index for each vertex into that array for transformation purposes?) If I do the matrix transformations on the CPU, It seems I can't really do the skinning on the GPU as the pre-transformed vertexes will wreck havoc with the calculations, so this seems not viable unless I am missing something Overall it seems like simplest solution is to just do all of the vertex manipulation on the CPU and pass the pre-transformed data to the GPU, using vertex shaders that do basically nothing.  This doesn't seem the most efficient use of the graphics hardware, but could potentially reduce the number of draw calls needed.

Really, I am looking for some advice on how to proceed with this, how something like this is typically handled.  Are the multiple draw calls and skinning calculations not a huge deal?  I would LIKE to save as much of the CPU's time per frame so it can be tasked with other things, as to keep CPU resources open to the implementation of the engine.  However, that becomes a moot point if the GPU becomes a bottleneck.

• Hello!
I would like to introduce Diligent Engine, a project that I've been recently working on. Diligent Engine is a light-weight cross-platform abstraction layer between the application and the platform-specific graphics API. Its main goal is to take advantages of the next-generation APIs such as Direct3D12 and Vulkan, but at the same time provide support for older platforms via Direct3D11, OpenGL and OpenGLES. Diligent Engine exposes common front-end for all supported platforms and provides interoperability with underlying native API. Shader source code converter allows shaders authored in HLSL to be translated to GLSL and used on all platforms. Diligent Engine supports integration with Unity and is designed to be used as a graphics subsystem in a standalone game engine, Unity native plugin or any other 3D application. It is distributed under Apache 2.0 license and is free to use. Full source code is available for download on GitHub.
Features:
True cross-platform Exact same client code for all supported platforms and rendering backends No #if defined(_WIN32) ... #elif defined(LINUX) ... #elif defined(ANDROID) ... No #if defined(D3D11) ... #elif defined(D3D12) ... #elif defined(OPENGL) ... Exact same HLSL shaders run on all platforms and all backends Modular design Components are clearly separated logically and physically and can be used as needed Only take what you need for your project (do not want to keep samples and tutorials in your codebase? Simply remove Samples submodule. Only need core functionality? Use only Core submodule) No 15000 lines-of-code files Clear object-based interface No global states Key graphics features: Automatic shader resource binding designed to leverage the next-generation rendering APIs Multithreaded command buffer generation 50,000 draw calls at 300 fps with D3D12 backend Descriptor, memory and resource state management Modern c++ features to make code fast and reliable The following platforms and low-level APIs are currently supported:
Windows Desktop: Direct3D11, Direct3D12, OpenGL Universal Windows: Direct3D11, Direct3D12 Linux: OpenGL Android: OpenGLES MacOS: OpenGL iOS: OpenGLES API Basics
Initialization
The engine can perform initialization of the API or attach to already existing D3D11/D3D12 device or OpenGL/GLES context. For instance, the following code shows how the engine can be initialized in D3D12 mode:
#include "RenderDeviceFactoryD3D12.h" using namespace Diligent; // ...  GetEngineFactoryD3D12Type GetEngineFactoryD3D12 = nullptr; // Load the dll and import GetEngineFactoryD3D12() function LoadGraphicsEngineD3D12(GetEngineFactoryD3D12); auto *pFactoryD3D11 = GetEngineFactoryD3D12(); EngineD3D12Attribs EngD3D12Attribs; EngD3D12Attribs.CPUDescriptorHeapAllocationSize[0] = 1024; EngD3D12Attribs.CPUDescriptorHeapAllocationSize[1] = 32; EngD3D12Attribs.CPUDescriptorHeapAllocationSize[2] = 16; EngD3D12Attribs.CPUDescriptorHeapAllocationSize[3] = 16; EngD3D12Attribs.NumCommandsToFlushCmdList = 64; RefCntAutoPtr<IRenderDevice> pRenderDevice; RefCntAutoPtr<IDeviceContext> pImmediateContext; SwapChainDesc SwapChainDesc; RefCntAutoPtr<ISwapChain> pSwapChain; pFactoryD3D11->CreateDeviceAndContextsD3D12( EngD3D12Attribs, &pRenderDevice, &pImmediateContext, 0 ); pFactoryD3D11->CreateSwapChainD3D12( pRenderDevice, pImmediateContext, SwapChainDesc, hWnd, &pSwapChain ); Creating Resources
Device resources are created by the render device. The two main resource types are buffers, which represent linear memory, and textures, which use memory layouts optimized for fast filtering. To create a buffer, you need to populate BufferDesc structure and call IRenderDevice::CreateBuffer(). The following code creates a uniform (constant) buffer:
BufferDesc BuffDesc; BufferDesc.Name = "Uniform buffer"; BuffDesc.BindFlags = BIND_UNIFORM_BUFFER; BuffDesc.Usage = USAGE_DYNAMIC; BuffDesc.uiSizeInBytes = sizeof(ShaderConstants); BuffDesc.CPUAccessFlags = CPU_ACCESS_WRITE; m_pDevice->CreateBuffer( BuffDesc, BufferData(), &m_pConstantBuffer ); Similar, to create a texture, populate TextureDesc structure and call IRenderDevice::CreateTexture() as in the following example:
TextureDesc TexDesc; TexDesc.Name = "My texture 2D"; TexDesc.Type = TEXTURE_TYPE_2D; TexDesc.Width = 1024; TexDesc.Height = 1024; TexDesc.Format = TEX_FORMAT_RGBA8_UNORM; TexDesc.Usage = USAGE_DEFAULT; TexDesc.BindFlags = BIND_SHADER_RESOURCE | BIND_RENDER_TARGET | BIND_UNORDERED_ACCESS; TexDesc.Name = "Sample 2D Texture"; m_pRenderDevice->CreateTexture( TexDesc, TextureData(), &m_pTestTex ); Initializing Pipeline State
Diligent Engine follows Direct3D12 style to configure the graphics/compute pipeline. One big Pipelines State Object (PSO) encompasses all required states (all shader stages, input layout description, depth stencil, rasterizer and blend state descriptions etc.)
To create a shader, populate ShaderCreationAttribs structure. An important member is ShaderCreationAttribs::SourceLanguage. The following are valid values for this member:
SHADER_SOURCE_LANGUAGE_DEFAULT  - The shader source format matches the underlying graphics API: HLSL for D3D11 or D3D12 mode, and GLSL for OpenGL and OpenGLES modes. SHADER_SOURCE_LANGUAGE_HLSL  - The shader source is in HLSL. For OpenGL and OpenGLES modes, the source code will be converted to GLSL. See shader converter for details. SHADER_SOURCE_LANGUAGE_GLSL  - The shader source is in GLSL. There is currently no GLSL to HLSL converter. To allow grouping of resources based on the frequency of expected change, Diligent Engine introduces classification of shader variables:
Static variables (SHADER_VARIABLE_TYPE_STATIC) are variables that are expected to be set only once. They may not be changed once a resource is bound to the variable. Such variables are intended to hold global constants such as camera attributes or global light attributes constant buffers. Mutable variables (SHADER_VARIABLE_TYPE_MUTABLE) define resources that are expected to change on a per-material frequency. Examples may include diffuse textures, normal maps etc. Dynamic variables (SHADER_VARIABLE_TYPE_DYNAMIC) are expected to change frequently and randomly. This post describes the resource binding model in Diligent Engine.
The following is an example of shader initialization:
To create a pipeline state object, define instance of PipelineStateDesc structure. The structure defines the pipeline specifics such as if the pipeline is a compute pipeline, number and format of render targets as well as depth-stencil format:
// This is a graphics pipeline PSODesc.IsComputePipeline = false; PSODesc.GraphicsPipeline.NumRenderTargets = 1; PSODesc.GraphicsPipeline.RTVFormats[0] = TEX_FORMAT_RGBA8_UNORM_SRGB; PSODesc.GraphicsPipeline.DSVFormat = TEX_FORMAT_D32_FLOAT; The structure also defines depth-stencil, rasterizer, blend state, input layout and other parameters. For instance, rasterizer state can be defined as in the code snippet below:
// Init rasterizer state RasterizerStateDesc &RasterizerDesc = PSODesc.GraphicsPipeline.RasterizerDesc; RasterizerDesc.FillMode = FILL_MODE_SOLID; RasterizerDesc.CullMode = CULL_MODE_NONE; RasterizerDesc.FrontCounterClockwise = True; RasterizerDesc.ScissorEnable = True; //RSDesc.MultisampleEnable = false; // do not allow msaa (fonts would be degraded) RasterizerDesc.AntialiasedLineEnable = False; When all fields are populated, call IRenderDevice::CreatePipelineState() to create the PSO:
Shader resource binding in Diligent Engine is based on grouping variables in 3 different groups (static, mutable and dynamic). Static variables are variables that are expected to be set only once. They may not be changed once a resource is bound to the variable. Such variables are intended to hold global constants such as camera attributes or global light attributes constant buffers. They are bound directly to the shader object:

m_pPSO->CreateShaderResourceBinding(&m_pSRB); Dynamic and mutable resources are then bound through SRB object:
m_pSRB->GetVariable(SHADER_TYPE_VERTEX, "tex2DDiffuse")->Set(pDiffuseTexSRV); m_pSRB->GetVariable(SHADER_TYPE_VERTEX, "cbRandomAttribs")->Set(pRandomAttrsCB); The difference between mutable and dynamic resources is that mutable ones can only be set once for every instance of a shader resource binding. Dynamic resources can be set multiple times. It is important to properly set the variable type as this may affect performance. Static variables are generally most efficient, followed by mutable. Dynamic variables are most expensive from performance point of view. This post explains shader resource binding in more details.
Setting the Pipeline State and Invoking Draw Command
Before any draw command can be invoked, all required vertex and index buffers as well as the pipeline state should be bound to the device context:
// Clear render target const float zero[4] = {0, 0, 0, 0}; m_pContext->ClearRenderTarget(nullptr, zero); // Set vertex and index buffers IBuffer *buffer[] = {m_pVertexBuffer}; Uint32 offsets[] = {0}; Uint32 strides[] = {sizeof(MyVertex)}; m_pContext->SetVertexBuffers(0, 1, buffer, strides, offsets, SET_VERTEX_BUFFERS_FLAG_RESET); m_pContext->SetIndexBuffer(m_pIndexBuffer, 0); m_pContext->SetPipelineState(m_pPSO); Also, all shader resources must be committed to the device context:
m_pContext->CommitShaderResources(m_pSRB, COMMIT_SHADER_RESOURCES_FLAG_TRANSITION_RESOURCES); When all required states and resources are bound, IDeviceContext::Draw() can be used to execute draw command or IDeviceContext::DispatchCompute() can be used to execute compute command. Note that for a draw command, graphics pipeline must be bound, and for dispatch command, compute pipeline must be bound. Draw() takes DrawAttribs structure as an argument. The structure members define all attributes required to perform the command (primitive topology, number of vertices or indices, if draw call is indexed or not, if draw call is instanced or not, if draw call is indirect or not, etc.). For example:
DrawAttribs attrs; attrs.IsIndexed = true; attrs.IndexType = VT_UINT16; attrs.NumIndices = 36; attrs.Topology = PRIMITIVE_TOPOLOGY_TRIANGLE_LIST; pContext->Draw(attrs); Tutorials and Samples
The GitHub repository contains a number of tutorials and sample applications that demonstrate the API usage.

AntTweakBar sample demonstrates how to use AntTweakBar library to create simple user interface.

Atmospheric scattering sample is a more advanced example. It demonstrates how Diligent Engine can be used to implement various rendering tasks: loading textures from files, using complex shaders, rendering to textures, using compute shaders and unordered access views, etc.

The repository includes Asteroids performance benchmark based on this demo developed by Intel. It renders 50,000 unique textured asteroids and lets compare performance of D3D11 and D3D12 implementations. Every asteroid is a combination of one of 1000 unique meshes and one of 10 unique textures.

Integration with Unity
Diligent Engine supports integration with Unity through Unity low-level native plugin interface. The engine relies on Native API Interoperability to attach to the graphics API initialized by Unity. After Diligent Engine device and context are created, they can be used us usual to create resources and issue rendering commands. GhostCubePlugin shows an example how Diligent Engine can be used to render a ghost cube only visible as a reflection in a mirror.

• By Yxjmir
I'm trying to load data from a .gltf file into a struct to use to load a .bin file. I don't think there is a problem with how the vertex positions are loaded, but with the indices. This is what I get when drawing with glDrawArrays(GL_LINES, ...):

Also, using glDrawElements gives a similar result. Since it looks like its drawing triangles using the wrong vertices for each face, I'm assuming it needs an index buffer/element buffer. (I'm not sure why there is a line going through part of it, it doesn't look like it belongs to a side, re-exported it without texture coordinates checked, and its not there)
I'm using jsoncpp to load the GLTF file, its format is based on JSON. Here is the gltf struct I'm using, and how I parse the file:
glBindVertexArray(g_pGame->m_VAO);
glDrawElements(GL_LINES, g_pGame->m_indices.size(), GL_UNSIGNED_BYTE, (void*)0); // Only shows with GL_UNSIGNED_BYTE
glDrawArrays(GL_LINES, 0, g_pGame->m_vertexCount);
So, I'm asking what type should I use for the indices? it doesn't seem to be unsigned short, which is what I selected with the Khronos Group Exporter for blender. Also, am I reading part or all of the .bin file wrong?
Test.gltf
Test.bin

• That means how do I use base DirectX or OpenGL api's to make a physics based destruction simulation?
Will it be just smart rendering or something else is required?

# OpenGL OpenGL ES 2 Texture Not Rendering

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## Recommended Posts

I'm porting my game framework from OpenGL 3/4 to OpenGL ES 2 but I'm having an issue where textures aren't being rendered.

In once instance I'm using simple vertex buffer objects to store the vertices and texcoords. In my OpenGL code these are bound in vertex arrays but I understand they aren't used in ES. Basically, I have some initialisation code where I do this:

[source lang="cpp"]
//glGenVertexArrays(1, &m_vao); //Not used in GLES.
glGenBuffers(2, m_vbo);

//glBindVertexArray(m_vao); //Not used in GLES.

glBindBuffer(GL_ARRAY_BUFFER, m_vbo[0]);
glBufferData(GL_ARRAY_BUFFER, 4 * sizeof(Vector2), ms_verts, GL_STATIC_DRAW);

glBindBuffer(GL_ARRAY_BUFFER, m_vbo[1]);
glBufferData(GL_ARRAY_BUFFER, 4 * sizeof(Vector2), ms_texCoords, GL_STATIC_DRAW);
[/source]

And then when it comes time to render I do this:

[source lang="cpp"]

int32_t* pUniformHandle = m_uniforms.Find(textureParamName);

if (pUniformHandle)
{
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, m_textureHandle);
glUniform1i(*pUniformHandle, 0);
}

//glBindVertexArray(m_vao); //Not used in GLES.

glBindBuffer(GL_ARRAY_BUFFER, m_vbo[0]);
glVertexAttribPointer(Effect::POSITION_ATTR, 2, GL_FLOAT, GL_FALSE, 0, 0);
glEnableVertexAttribArray(Effect::POSITION_ATTR);

glBindBuffer(GL_ARRAY_BUFFER, m_vbo[1]);
glVertexAttribPointer(Effect::TEXCOORD0_ATTR, 2, GL_FLOAT, GL_FALSE, 0, 0);
glEnableVertexAttribArray(Effect::TEXCOORD0_ATTR);

glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

glDisableVertexAttribArray(Effect::TEXCOORD0_ATTR);
glDisableVertexAttribArray(Effect::POSITION_ATTR);
[/source]

In OpenGL (with those "Not used in GLES" bits uncommented) this works fine but in GLES the prims are being rendered but the texture isn't being applied. For reference, my shader looks like this:

[source lang="plain"]
uniform mat4 worldMatrix;
uniform mat4 projectionMatrix;

attribute vec2 aPosition;
attribute vec2 aTexCoord;

varying vec2 vTexCoord;

void main()
{
vTexCoord = aTexCoord;
mat4 worldProjMatrix = projectionMatrix * worldMatrix;
gl_Position = worldProjMatrix * vec4(aPosition, 0.0, 1.0);
}
[/source]

[source lang="plain"]
uniform sampler2D texture;
uniform vec4 colour;

varying vec2 vTexCoord;

void main()
{
gl_FragColor = texture2D(texture, vTexCoord) * colour;
}
[/source]

Can anyone see what I'm doing wrong? I've been scanning through the GLES book but I can't see anything obvious.

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In OpenGL (with those "Not used in GLES" bits uncommented) this works fine but in GLES the prims are being rendered but the texture isn't being applied

To be precise, there is no such thing 'the texture isn't being applied'. What do you mean exactly? The geometry renders properly, but all rasterized fragments come out black (i.e. the texture2D call in the shader comes out black) ?

I have run into such cases several times with GLES2, and searching the codebase, I find I have added these checks:

 /* GLES2 Tegra2(?) bug: If you specify wrap for texture S coordinate and clamp for texture T coordinate, and the texture width is pow2, but height is not, the wrap operation will silently fail and be treated as a clamp operation. */ /* Sanity check to avoid GLES2 SILENT FAILURES: http://www.khronos.org/opengles/sdk/docs/man/xhtml/glTexParameter.xml If the texture does not have mipmaps, specifying MIN filter of GL_xxx_MIPMAP_xxx will succeed, but silently render black. */ const bool hasMipmaps = targetTexture->NumMipmaps() > 1; if (hasMipmaps) { if (!IsPow2(targetTexture->Width()) || !IsPow2(targetTexture->Height())) { LOGE("ApplyTextureSampler Error: GLES2 will now silently render black since mipmapping was specified for a non-pow2 texture! Killing mipmaps from texture '%s' as a workaround.", targetTexture->Name().c_str()); targetTexture->DisableMipmaps(); } } 

 /* Sanity check to detect GLES2 SILENT FAILURES: http://www.khronos.org/opengles/sdk/docs/man/xhtml/glTexParameter.xml " if the width or height of a texture image are not powers of two and either the GL_TEXTURE_MIN_FILTER is set to one of the functions that requires mipmaps or the GL_TEXTURE_WRAP_S or GL_TEXTURE_WRAP_T is not set to GL_CLAMP_TO_EDGE, then the texture image unit will return (R, G, B, A) = (0, 0, 0, 1). " */ if ((textureSampler->addressU != TextureAddressClamp || textureSampler->addressV != TextureAddressClamp) && (!IsPow2(targetTexture->Width()) || !IsPow2(targetTexture->Height()))) LOGE("ApplyTextureSampler Error: GLES2 doesn't support other addressing modes than GL_CLAMP_TO_EDGE when size is not pow2! Size was %dx%d in texture '%s'. (GLES2 will now silently render black)", targetTexture->Width(), targetTexture->Height(), targetTexture->Name().c_str()); 

The page http://www.khronos.org/opengles/sdk/docs/man/xhtml/glTexParameter.xml documents

Suppose that a texture is accessed from a fragment shader or vertex shader and has set GL_TEXTURE_MIN_FILTER to one of the functions that requires mipmaps. If either the dimensions of the texture images currently defined (with previous calls to glTexImage2D, glCompressedTexImage2D, or glCopyTexImage2D) do not follow the proper sequence for mipmaps (described above), or there are fewer texture images defined than are needed, or the set of texture images were defined with different formats or types, then the texture image unit will return (R, G, B, A) = (0, 0, 0, 1).

Similarly, if the width or height of a texture image are not powers of two and either the GL_TEXTURE_MIN_FILTER is set to one of the functions that requires mipmaps or the GL_TEXTURE_WRAP_S or GL_TEXTURE_WRAP_T is not set to GL_CLAMP_TO_EDGE, then the texture image unit will return (R, G, B, A) = (0, 0, 0, 1).
[/quote]

Needless to say, the very existence of documented silent failure cases for an API (combined with the lack of a documented way to set up a debug mode that would properly detect these) is a major picard facepalm.jpg situation.

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[color=#282828][font=helvetica, arial, verdana, tahoma, sans-serif]

### [background=rgb(250, 251, 252)]To be precise, there is no such thing 'the texture isn't being applied'. What do you mean exactly? The geometry renders properly, but all rasterized fragments come out black (i.e. the texture2D call in the shader comes out black) ?[/background][/font]

Sorry, yes, I was generalising as I wrote the post quickly but yeah the geometry renders correctly but black. If I change the fragment shader to output a defined colour like, say gl_FragColour = vec4(1.0, 0.0, 0.0, 1.0); then it renders with the colour I supplied instead of black. But when I use the texture2D function I just get black prims.

The particular texture I'm trying to display is 512x512 so that rules out the power of two thing. I've also just tried setting GL_TEXTURE_WRAP_S and GL_TEXTURE_WRAP_T to GL_CLAMP_TO_EDGE and GL_TEXTURE_MIN_FILTER and FL_TEXTURE_MAG_FILTER to GL_LINEAR but it hasn't made a difference.

Also, not sure if it makes a difference but I am using ATI's GLES SDK in Windows. My plan was to get it working in Windows, so I know it's working, before I move it across to my Raspberry Pi, which is my ultimate goal.

I'll have more of a look tomorrow as I'm done for tonight.

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The OpenGL ES 2 Windows® SDK’s do not work exactly the same as on real devices, but you should at least be able to display textures.

There can be many reasons for getting black textures.

1. [s]If mipmaps are enabled but the image does not have a full mipmap chain supplied (full meaning down to 1×1).[/s]
2. [s]If the texture is not a power of 2 and the wrap modes are not set to GL_CLAMP_TO_EDGE.[/s]
3. [s]If the texture is not being activated in the appropriate slot.[/s]
4. [s]If the sampler has not been assigned to that slot.[/s]
5. If the texture coordinates are absent or incorrect.
6. If “colour” has not been assigned.

I give you the benefit of a doubt on #4, since I see code that is attempting to set the sampler to 0, but I have no way of knowing if the handle is actually valid or not. But samplers default to 0 anyway so that won’t be your problem.

Which means you have 2 more things to test.
Test #5 by printing the texture coordinates.

gl_FragColor = vec4( vTexCoord.x, vTexCoord.y, 0.0, 1.0 );

Test #6 by removing “colour” from the equation. I don’t see anywhere where you are setting that value.

L. Spiro

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I like #5, it's a clever way of seeing the texture coordinates are valid. Alas, mine were, black top-left, red top-right, green bottom-left, yellow bottom-right.

I am setting the colour value (though I know in my code I only showed me setting the texture uniform) but just to double check I removed colour from the gl_FragColor calculation and I'm still getting a black square.

I did think perhaps something isn't working in the GLES Windows SDK and that I should just port my code to Pi and fix the issue on there, if it's still an issue. That being said, if I run the Simple_Texture2D sample from the GLES book then the texture displays correctly. The only difference I can see between my code and theirs, however, is that they use glVertexAttribPointer to send the data to the GPU each render instead of storing the data off in a VBO. Should this make a difference? Edited by redneon

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I just quickly tried sacking off the VBOs and using glVertexAttribPointer to send the data to the GPU each render, as in the Simple_Texture2D sample like this:

[source lang="cpp"]
glVertexAttribPointer(Effect::POSITION_ATTR, 2, GL_FLOAT, GL_FALSE, 0, ms_verts);
glVertexAttribPointer(Effect::TEXCOORD0_ATTR, 2, GL_FLOAT, GL_FALSE, 0, ms_texCoords);

glEnableVertexAttribArray(Effect::POSITION_ATTR);
glEnableVertexAttribArray(Effect::TEXCOORD0_ATTR);

glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

glDisableVertexAttribArray(Effect::TEXCOORD0_ATTR);
glDisableVertexAttribArray(Effect::POSITION_ATTR);
[/source]

But now even the geometry isn't being rendered. I've probably done something stupid but I only had a quick five minutes before I go to work so I thought I'd give it a try. I'll have more of a look when I get back from work.

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I've fixed why the geometry wasn't being rendered when I don't use VBOs (I was being an idiot and hadn't unbound a buffer I was using elsewhere). So, I've got the geometry rending both with and without VBOs but in both instances I'm just getting black prims without the texture.

I'm now trying to match my code as closely as possible to the Simple_Texture2D sample. The first step was removing the VBOs, I've also tried using their texture code too but it hasn't made a difference. There must be something obviously different between my code and theirs though, for theirs to be working and mine not. I'm sure I'll get to the bottom of it if I keep chugging away

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Just thinking, is there any chance that I could have set my window up incorrectly? Maybe something wrong in the EGL stuff? I don't think that this could cause this issue but I'm just clutching at straws really, as I can't see any difference between my code and the Simple_Texture2D code.

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Try assuming that it is an asset difference rather than a code difference. Try with a known working texture asset. Or try starting from the working sample and try to evolve it towards your breaking testcase one by one to see where it breaks.

I don't think there's anything in the EGL spec that would affect how texture2D sampling is done in the shader code.

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Bloody hell. I've fixed it and, as per usual with these things, it was user error. I was passing an incorrect value into glTexImage2D for the internal format. If you look at my texture load code below you can see I'm incorrectly passing bitDepth into glTexImage2D instead of textureFormat. Doh! I've no idea how this works correctly in normal OpenGL, though. I would expect it to fail like it does in GLES. Ah well, nevermind.
[source lang="cpp"]int32_t width, height, bitDepth = 0;
uint8_t* pData = ::stbi_load_from_memory(rTextureFile.GetData(), rTextureFile.GetSize(), &width, &height, &bitDepth, 0);

if (pData)
{
m_width = width;
m_height = height;
m_bitDepth = bitDepth;

uint32_t textureFormat = bitDepth == 4 ? GL_RGBA : GL_RGB;
glGenTextures(1, &m_handle);
glBindTexture(GL_TEXTURE_2D, m_handle);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

glTexImage2D(GL_TEXTURE_2D,
0,
bitDepth,
width,
height,
0,
textureFormat,
GL_UNSIGNED_BYTE,
pData);

//No longer need the image.
stbi_image_free(pData);

return true;
}

return false;
[/source]