# OpenGL Terrain Rendering Issue

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Good evening everyone :) Ive just had my first attempt at creating a terrain from a height map (image). I guess its not terrible haha but it not how it should be. Im using OpenGL and Triangle Strips. Here is a screen shot of my terrain looking down on it: So hopefully u can see the liny effect im getting. Below is the code i use for building the terrain. Its not too long so dont be worried :)

public class TerrainBuilder
{

public TerrainBuilder()
{

}

public int createDisplayList(String mapFile, GL11 gl){

int dL = 0;

int width = getImageWidth(mapFile);
int height = getImageHeight(mapFile);

int heightMap[][] = loadMap(mapFile, width, height);

dL = gl.glGenLists(1);

gl.glNewList(dL, gl.GL_COMPILE);

for(int y = 0; y < height - 2; y++){

gl.glBegin(gl.GL_TRIANGLE_STRIP);

for(int x = 0; x < width; x++){

float xV = x * 2;
float yV = (float)(heightMap[y][x]);
float zV = -1 * y * 1;

float xV1 = x * 2;
float yV1 = (float)(heightMap[y + 1][x] );
float zV1 = -1 * (y + 1) * 1;

float vx = yV * zV1 - zV * yV1;

float vy = zV * xV1 - xV * zV1;

float vz = xV * yV1 - yV * xV1;

float i = (float)Math.sqrt(vx*vx + vy*vy + vz*vz);

if(yV < 0 || yV1 < 0){
System.out.println("Bellow 0 Y at: " + x + ", " + y);
}

vx = vx / i;
vy = vy / i;
vz = vz / i;

gl.glNormal3f(vx, vy, vz);

gl.glTexCoord2f(0.0f, 1.0f);
gl.glVertex3f(xV, yV, zV);

float nx1 = x * 2;
float ny1 = (float)(heightMap[y + 1][x]);
float nz1 = -1 * (y + 1) * 1;

float nx2 = (x + 1) * 2;
float ny2 = (float)(heightMap[y + 2][x]);
float nz2 = -1 * (y + 2) * 1;

vx = ny1 * nz2 - nz1 * ny2;

vy = nz1 * nx2 - nx1 * nz2;

vz = nx1 * ny2 - ny1 * nx2;

i = (float)Math.sqrt(vx*vx + vy*vy + vz*vz);

vx = vx / i;
vy = vy / i;
vz = vz / i;

gl.glNormal3f(vx, vy, vz);

gl.glTexCoord2f(0.0f, 0.0f);
gl.glVertex3f(xV1, yV1, zV1);

}

gl.glEnd();

}

gl.glEndList();

return dL;

}

public int getImageHeight(String file){

int height = new ImageIcon(file).getIconHeight();

return height;

}

public int getImageWidth(String file){

int width = new ImageIcon(file).getIconWidth();

return width;

}

public int[][] loadMap(String fileName, int width, int height){

//Scale 0 - 15

Image mapImg = new ImageIcon(fileName).getImage();
int heightMap[][] = new int[height][width];

BufferedImage map = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics g = map.createGraphics();

Color color = new Color(map.getRGB(0,0));
float greyScale = (float)(0.30 * color.getRed() + 0.59 * color.getGreen() + 0.11 * color.getBlue());

float min = greyScale;
float max = greyScale;

g.drawImage(mapImg, 0, 0, null);

for(int y = 0; y < height; y++){
for(int x = 0; x < width; x++){

color = new Color(map.getRGB(x,y));

greyScale = (float)(0.30 * color.getRed() + 0.59 * color.getGreen() + 0.11 * color.getBlue());

if(greyScale < min){
min = greyScale;
}
if(greyScale > max){
max = greyScale;
}

heightMap[y][x] = (int)greyScale;

}
}

System.out.println("Min: " + min + ", Max: " + max);

float diff = max - min;
float scaleSec = diff / 25;

System.out.println("Scale Sections: " + scaleSec);

for(int y = 0; y < height; y++){
for(int x = 0; x < width; x++){

heightMap[y][x] = (int)(heightMap[y][x] / scaleSec);

}
}
return heightMap;
}

}


So yes, im using Java and LWJGL. Im guess the reason i am getting that liney effect is because i may be using the triangle strips incorrectly? Thats just my only thought on wat could be incorrect with my terrain. Im building the terrain with this height map: Any help would be greatly appreciated, Cheers, Nick!!!

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Are you sure everyting is in order with the image format etc? If you are unsure, try saving the map as a grayscale.

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Yeah, make sure the image is not in "interlaced" form.

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hi,

hmm I would bet on a lighting problem. If you try to concentrate on the height, it seems to be continous, So I think there's nothing wrond with the strips iteslf. But the bottom line of vertices in a strip is always black, and I'm pretty sure you made a mistake when you compute the normal of one of the 2 vertex (inside the drawStrip loop)

I tried to understand the code that compute the normal, but I don't understand anything, although I compute normals from a heightfield in my engine ^^
And after more looking of your screenshots, most normals seem wrong.

To compute the normals, you need to take at least 3 points in your heightfiel, but in your code, you only take 2 ...

if you want the normal of vertex[x][y], its as follow :

vertex1 = vector3(x * 2,        heightMap[x][y],      y * 2);vertex2 = vector3((x + 1) * 2,  heightMap[x + 1][y],  y * 2);vertex3 = vector3(x * 2,        heightMap[x][y + 1],  (y + 1) * 2);edge1  = vertex2 - vertex1;edge2  = vertex3 - vertex1;normal = normalize(crossProduct(edge1, edge2);

I use pseudo functions to make the understanding simpler. Try that, I really think the problem is with the lighting.

One way to check : disable lighting and siwtch to wireframe display

[/edit]

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Nick,

Thanks for your replies, just a quick question, how do u switch to wireframe?

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Nick,

Thanks for your replies, just a quick question, how do u switch to wireframe?

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arg, I didn't realize that you're probably in OpenGL ^^'
in DirectX, it's just a d3dDevice->SetRenderState(D3DRS_FILLMODE, D3DFILL_WIREFRAME); but in OpenGL, you can't (as far as I remember ... didn't code in OpenGL since a looooonng time ^^)

Well, at least, to check if your grid is well drawn (no error in the vertices position, replace the loop that draw the strips by a loop that simply draw the vertices (gl.glBegin(gl.GL_POINT_LIST); or similar) This way, you can see if your vertices are well placed. If it's the case (I believe it is) then, the problem clearly comes from the lighting. So, you'll have to correct the code that compute the normals ^^

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Use glPolygonMode(GL_FRONT_AND_BACK, GL_LINE) to switch to wireframe.

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Ok here is a screen from the wireframe view, thanks for the tip btw:

To me it looks like a lighting problem, as suggested by others above, but before i look into the normals can anyone just approve of the diagnosis?

Cheers, Nick :)

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Your texture coordinates are fixed numbers ... and not only that, I only see 0,0 and 0,1 in the code. Neither of these can be right, surely? . . . try disabling textures and rendering it, so that you know for sure it is lighting and not the thing being lit . . .

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Nah its not the texturing that is causing the problem, that was just left from some old code, there is not texture attached, and i did run it disabling texturing and stilll same result, i think it is definately a normal problem, normal being the normal used in lighting.

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It looks like there's something wrong with the lighting, as has been mentioned. Have another look at the code that generates the vertex normals.

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Haha ok im struggling, could someone please give me a breif lesson in how to compute normals for triangle strips? Im really new to this stufff and hvnt dont much vector work in yr11 yet, touched on it in physics and a little in math but i hvnt grasped it yet.

Cheers!!!

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hi, I gave you some pseudo code for that a few post earlier ^^

basically, imagine that you have a heightmap grid like height[512][512]. The code is :

for (int x = 0; x < 511; x++){   for (int y = 0; y < 511; y++)   {      // these 2 vertices are the ones used for the strip      vertex1.x = x;      vertex1.y = height[x][y];      vertex1.z = y;      vertex2.x = x;      vertex2.y = height[x][y + 1];      vertex2.z = y + 1;      // now, for vertex1, take the next one in the X axis AND in the Z axis       nextX.x = x + 1;      nextX.y = height[x + 1][y];      nextX.z = y;      nextY.x = x;      nextY.y = height[x][y + 1];      nextY.z = y + 1;      // now, cross product between the 2 rays going from vertex1 to nextX and nextY      ray1 = nextX - vertex1;      ray2 = nextY - vertex1;      // replace the cross product and normalization by your code      normal1 = crossProduct(ray1, ray2);      normal1 = normalize(normal1);      // now, do it for the second vertex      nextX.x = x + 1;      nextX.y = height[x + 1][y + 1];      nextX.z = y + 1;      nextY.x = x;      nextY.y = height[x][y + 2];      nextY.z = y + 2;      ray1 = nextX - vertex1;      ray2 = nextY - vertex1;      normal2 = crossProduct(ray1, ray2);      normal2 = normalize(normal2);      // now, you have your vertices and normals.   }}

Maybe there's some error in this code, i just poped it out of my mind. But the principle is there : for a given vertex ((x, y) in the heightmap table) just extract a neighbour vertex in the x coordinate (e.g of coordinate (x + 1, y) or (x - 1, y) and a neighbour vertex in the y coordinate. Substracting these 2 new position to your current position, you'll get 2 rays that you can use to compute the normal by simply computing a cross product and normalizing.

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Quote:
 Original post by NickyP101Haha ok im struggling, could someone please give me a breif lesson in how to compute normals for triangle strips? Im really new to this stufff and hvnt dont much vector work in yr11 yet, touched on it in physics and a little in math but i hvnt grasped it yet.Thanks in advance, Nick :)Cheers!!!

Heres a thread I made earlier on how I do this. Since it's a terrain, calculating up front is best. If you need dynamic calculations, like for water, then there should be a shortcut routine in there also.

hth
F451

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Ok after alot of learning and alot of help from all you :) i think ive partially fixed the problem, below is a screen shot of the latest:

Now my question is: See how the terrain looks soo pointy? how do i make it look smoother??

Cheers, Nick.

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Make your heightmap smoother. (On a sidenote, it would be kind of you to use smaller images in the future. Those high resolution pictures can really hog bandwith.)

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Run a gaussian blur over your heightmap. I noticed that the image you posted was pretty noisy, which will cause a lot of "spikes" in your terrain.
Also, make sure that you're saving the map at a high color depth, prefferably in a lossless format. Any dithering will cause artifacts like you're getting here, so GIFs don't work well for heightmaps, and JPEGs can give you unpleasant banding. TGAs or BMPs are best (RAW also works, but it doesn't have all the nice header info the other two have, which can be restrictive.)
Touching on the color depth again, it's also a good idea not to have a 1-1 corrospondance from pixle color to height. If you have a 256 color range and your landscape is 256 units high at it's peak, then every elevation change is going to be at least 1 unit. If you're landscape verts are spaced 1 unit apart, this means a MINIMUM angle of 45 degrees. (Think SimCity 2000's landscape.) If your max terrain height is only 64 units, though, then each progressive color value represents a half-unit change in height. Now your miminum angle is 22.5 degrees, which gives a much smoother appearance, and allows for more natural hills and such.

...I'm rambling again, aren't I? I'll stop. ^_^

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Here's a gamedev article on this : http://www.gamedev.net/reference/articles/article2164.asp

and a routine I use that was inspired by it, which gives a simple smoothing by averaging between neighbouring vertices. Looks clunky, and is not optimised, but it's simple enough to follow. I use and adjustment value of 1.0f:

//// Smooth heightmap based on averaging neighbouring vertices// Neighbour vertices chosen are dependent upon location on heightmap// so as to give better overall results//void SmoothTerrain(float adjust){  for ( int r = 0; r < hmap.size; r++ ) {    for ( int c = 0; c < hmap.size; c++ ) {      if ( r == 0 && c == 0 ) {        // back left corner - average 3 vertices        hmap.vert[r][c].y = ((hmap.vert[r+1][c].y*adjust)+(hmap.vert[r+1][c+1].y*adjust)+(hmap.vert[r][c+1].y*adjust))/3.0f;      } else if ( (r > 0 && r < (hmap.size-1)) && c == 0 ) {        // left edge - average 5 vertices        hmap.vert[r][c].y = ((hmap.vert[r+1][c].y*adjust)+(hmap.vert[r+1][c+1].y*adjust)+(hmap.vert[r][c+1].y*adjust)+(hmap.vert[r-1][c+1].y*adjust)+(hmap.vert[r-1][c].y*adjust))/5.0f;      } else if ( r == (hmap.size-1) && c == 0  ) {        // front left corner - 3        hmap.vert[r][c].y = ((hmap.vert[r][c+1].y*adjust)+(hmap.vert[r-1][c+1].y*adjust)+(hmap.vert[r-1][c].y*adjust))/3.0f;      } else if ( r == (hmap.size-1) && (c > 0 && c < (hmap.size-1)) ) {        // front edge - average 5 vertices        hmap.vert[r][c].y = ((hmap.vert[r][c+1].y*adjust)+(hmap.vert[r-1][c+1].y*adjust)+(hmap.vert[r-1][c].y*adjust)+(hmap.vert[r-1][c-1].y*adjust)+(hmap.vert[r][c-1].y*adjust))/5.0f;      } else if ( r == (hmap.size-1) && c == (hmap.size-1) ) {        // front right corner - average 3 vertices        hmap.vert[r][c].y = ((hmap.vert[r-1][c].y*adjust)+(hmap.vert[r-1][c-1].y*adjust)+(hmap.vert[r][c-1].y*adjust))/3.0f;      } else if ( ( r > 0 && r < (hmap.size-1)) && c == (hmap.size-1)  ) {        // right edge - average 5 vertices        hmap.vert[r][c].y = ((hmap.vert[r-1][c].y*adjust)+(hmap.vert[r-1][c-1].y*adjust)+(hmap.vert[r][c-1].y*adjust)+(hmap.vert[r+1][c-1].y*adjust)+(hmap.vert[r+1][c].y*adjust))/5.0f;      } else if ( r == 0 && c == (hmap.size-1) ) {        // back right corner - average 3 vertices        hmap.vert[r][c].y = ((hmap.vert[r][c-1].y*adjust)+(hmap.vert[r+1][c-1].y*adjust)+(hmap.vert[r+1][c].y*adjust))/3.0f;      } else if ( r == 0 && ( c > 0 && c < (hmap.size-1)) ) {        // back edge - average 5 vertices        hmap.vert[r][c].y = ((hmap.vert[r][c-1].y*adjust)+(hmap.vert[r+1][c-1].y*adjust)+(hmap.vert[r+1][c].y*adjust)+(hmap.vert[r+1][c+1].y*adjust)+(hmap.vert[r][c+1].y*adjust))/5.0f;      } else {        // internal - average 8 vertices        hmap.vert[r][c].y = ((hmap.vert[r-1][c-1].y*adjust)+(hmap.vert[r][c-1].y*adjust)+(hmap.vert[r+1][c-1].y*adjust)+(hmap.vert[r+1][c].y*adjust)+(hmap.vert[r+1][c+1].y*adjust)+(hmap.vert[r][c+1].y*adjust)+(hmap.vert[r-1][c+1].y*adjust)+(hmap.vert[r-1][c].y*adjust))/8.0f;      }    }  }}

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Thank you all, and yeah i will make smaller images from now on :) Sorry about that.

Ill research what you guys have told me and get back to you soon!

Cheers, Nick!

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Ok i understand the algorithm and i hve now implemented it:

That is after two "smooths" using the algorithm suggested in averaging out the height with the surrounding heights.

You can probably notice that the hills look a little bit liny i think due to the lighting, do u think this is normal? Or hve i missed something?

Cheers, Nick

(Ive just selected a piece of the screen shot this time, if u would like smaller again just tell me :))

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Yeah, the lines are normals again. Are you calculating the normals before or after smoothing? It would be best to do it afterwards.

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I'm too lazy to read your code, but anyway. When you calculate the normal vector, are you doing it seperately for each strip? Because the strips will share vertices along the edges, so they must also share normal vectors. If it's not that, maybe your just using flat shading. But it doesn't look like it.

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Here is my code after fixing the first normal problem:

        dL = gl.glGenLists(1);                gl.glNewList(dL, gl.GL_COMPILE);                       for(int y = 0; y < height - 1; y++){                                        gl.glBegin(gl.GL_TRIANGLE_STRIP);                                        for(int x = 0; x < width - 1; x++){                                                Vector v1;                        Vector v2;                                                v1 = new Vector();                        v2 = new Vector();                                                v1.x = (x) - (x);                        v1.y = ((float)(heightMap[y + 1][x]) - (float)(heightMap[y][x]));                        v1.z = (y+1) - (y);                                                v2.x = (x + 1) - (x);                        v2.y = ((float)(heightMap[y][x + 1]) - (float)(heightMap[y][x]));                        v2.z = (y) - (y);                                                                                                float xV = x;                        float yV = (float)(heightMap[y][x]);                        float zV = -1 * y * 1;                                                float xV1 = x;                        float yV1 = (float)(heightMap[y + 1][x] );                        float zV1 = -1 * (y + 1) * 1;                            float vx = v1.y * v2.z - v2.y * v1.z;                        float vy = v2.x * v1.z - v1.x *  v2.z;                                float vz = v1.x * v2.y - v2.x * v1.y;                                                float i = (float)Math.sqrt(vx*vx + vy*vy + vz*vz);                                                                        vx = vx / i;                        vy = vy / i;                        vz = vz / i;                                                                        gl.glNormal3f(vx, vy, vz);                        gl.glVertex3f(xV, yV, zV);                        gl.glVertex3f(xV1, yV1, zV1);                                            }                                        gl.glEnd();                                }                                gl.glEndList();

Anything im not doing??

Cheers, Nick

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I'm sorry, this isn't a solution to your problem, but I think I noticed a few oddities in the code:

v1.x = (x) - (x);

Isn't that just equal to 0 ?

v2.x = (x + 1) - (x);

Is that not just equal to 1 ?

And what's with all the brackets?

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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. Graphics APIs usually have a native object that represents linear buffer. Diligent Engine uses IBuffer interface as an abstraction for a native buffer. To create a buffer, one needs to populate BufferDesc structure and call IRenderDevice::CreateBuffer() method as in the following example:
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 ); While there is usually just one buffer object, different APIs use very different approaches to represent textures. For instance, in Direct3D11, there are ID3D11Texture1D, ID3D11Texture2D, and ID3D11Texture3D objects. In OpenGL, there is individual object for every texture dimension (1D, 2D, 3D, Cube), which may be a texture array, which may also be multisampled (i.e. GL_TEXTURE_2D_MULTISAMPLE_ARRAY). As a result there are nine different GL texture types that Diligent Engine may create under the hood. In Direct3D12, there is only one resource interface. Diligent Engine hides all these details in ITexture interface. There is only one  IRenderDevice::CreateTexture() method that is capable of creating all texture types. Dimension, format, array size and all other parameters are specified by the members of the TextureDesc structure:
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 ); If native API supports multithreaded resource creation, textures and buffers can be created by multiple threads simultaneously.
Interoperability with native API provides access to the native buffer/texture objects and also allows creating Diligent Engine objects from native handles. It allows applications seamlessly integrate native API-specific code with Diligent Engine.
Next-generation APIs allow fine level-control over how resources are allocated. Diligent Engine does not currently expose this functionality, but it can be added by implementing IResourceAllocator interface that encapsulates specifics of resource allocation and providing this interface to CreateBuffer() or CreateTexture() methods. If null is provided, default allocator should be used.
Initializing the Pipeline State
As it was mentioned earlier, Diligent Engine follows next-gen APIs 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.). This approach maps directly to Direct3D12/Vulkan, but is also beneficial for older APIs as it eliminates pipeline misconfiguration errors. With many individual calls tweaking various GPU pipeline settings it is very easy to forget to set one of the states or assume the stage is already properly configured when in fact it is not. Using pipeline state object helps avoid these problems as all stages are configured at once.
While in earlier APIs shaders were bound separately, in the next-generation APIs as well as in Diligent Engine shaders are part of the pipeline state object. The biggest challenge when authoring shaders is that Direct3D and OpenGL/Vulkan use different shader languages (while Apple uses yet another language in their Metal API). Maintaining two versions of every shader is not an option for real applications and Diligent Engine implements shader source code converter that allows shaders authored in HLSL to be translated to GLSL. To create a shader, one needs to populate ShaderCreationAttribs structure. SourceLanguage member of this structure tells the system which language the shader is authored in:
When sampling a texture in a shader, the texture sampler was traditionally specified as separate object that was bound to the pipeline at run time or set as part of the texture object itself. However, in most cases it is known beforehand what kind of sampler will be used in the shader. Next-generation APIs expose new type of sampler called static sampler that can be initialized directly in the pipeline state. Diligent Engine exposes this functionality: when creating a shader, textures can be assigned static samplers. If static sampler is assigned, it will always be used instead of the one initialized in the texture shader resource view. To initialize static samplers, prepare an array of StaticSamplerDesc structures and initialize StaticSamplers and NumStaticSamplers members. Static samplers are more efficient and it is highly recommended to use them whenever possible. On older APIs, static samplers are emulated via generic sampler objects.
The following is an example of shader initialization:
Creating the Pipeline State Object
After all required shaders are created, the rest of the fields of the PipelineStateDesc structure provide depth-stencil, rasterizer, and blend state descriptions, the number and format of render targets, input layout format, etc. For instance, rasterizer state can be described as follows:
PipelineStateDesc PSODesc; RasterizerStateDesc &RasterizerDesc = PSODesc.GraphicsPipeline.RasterizerDesc; RasterizerDesc.FillMode = FILL_MODE_SOLID; RasterizerDesc.CullMode = CULL_MODE_NONE; RasterizerDesc.FrontCounterClockwise = True; RasterizerDesc.ScissorEnable = True; RasterizerDesc.AntialiasedLineEnable = False; Depth-stencil and blend states are defined in a similar fashion.
Another important thing that pipeline state object encompasses is the input layout description that defines how inputs to the vertex shader, which is the very first shader stage, should be read from the memory. Input layout may define several vertex streams that contain values of different formats and sizes:
// Define input layout InputLayoutDesc &Layout = PSODesc.GraphicsPipeline.InputLayout; LayoutElement TextLayoutElems[] = {     LayoutElement( 0, 0, 3, VT_FLOAT32, False ),     LayoutElement( 1, 0, 4, VT_UINT8, True ),     LayoutElement( 2, 0, 2, VT_FLOAT32, False ), }; Layout.LayoutElements = TextLayoutElems; Layout.NumElements = _countof( TextLayoutElems ); Finally, pipeline state defines primitive topology type. When all required members are initialized, a pipeline state object can be created by IRenderDevice::CreatePipelineState() method:
// Define shader and primitive topology PSODesc.GraphicsPipeline.PrimitiveTopologyType = PRIMITIVE_TOPOLOGY_TYPE_TRIANGLE; PSODesc.GraphicsPipeline.pVS = pVertexShader; PSODesc.GraphicsPipeline.pPS = pPixelShader; PSODesc.Name = "My pipeline state"; m_pDev->CreatePipelineState(PSODesc, &m_pPSO); When PSO object is bound to the pipeline, the engine invokes all API-specific commands to set all states specified by the object. In case of Direct3D12 this maps directly to setting the D3D12 PSO object. In case of Direct3D11, this involves setting individual state objects (such as rasterizer and blend states), shaders, input layout etc. In case of OpenGL, this requires a number of fine-grain state tweaking calls. Diligent Engine keeps track of currently bound states and only calls functions to update these states that have actually changed.
Direct3D11 and OpenGL utilize fine-grain resource binding models, where an application binds individual buffers and textures to certain shader or program resource binding slots. Direct3D12 uses a very different approach, where resource descriptors are grouped into tables, and an application can bind all resources in the table at once by setting the table in the command list. Resource binding model in Diligent Engine is designed to leverage this new method. It introduces a new object called shader resource binding that encapsulates all resource bindings required for all shaders in a certain pipeline state. It also introduces the classification of shader variables based on the frequency of expected change that helps the engine group them into tables under the hood:
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. Shader variable type must be specified during shader creation by populating an array of ShaderVariableDesc structures and initializing ShaderCreationAttribs::Desc::VariableDesc and ShaderCreationAttribs::Desc::NumVariables members (see example of shader creation above).
Static variables cannot be changed once a resource is bound to the variable. They are bound directly to the shader object. For instance, a shadow map texture is not expected to change after it is created, so it can be bound directly to the shader:
m_pPSO->CreateShaderResourceBinding(&m_pSRB); Note that an SRB is only compatible with the pipeline state it was created from. SRB object inherits all static bindings from shaders in the pipeline, but is not allowed to change them.
Mutable resources can only be set once for every instance of a shader resource binding. Such resources are intended to define specific material properties. For instance, a diffuse texture for a specific material is not expected to change once the material is defined and can be set right after the SRB object has been created:
m_pSRB->GetVariable(SHADER_TYPE_PIXEL, "tex2DDiffuse")->Set(pDiffuseTexSRV); In some cases it is necessary to bind a new resource to a variable every time a draw command is invoked. Such variables should be labeled as dynamic, which will allow setting them multiple times through the same SRB object:
m_pSRB->GetVariable(SHADER_TYPE_VERTEX, "cbRandomAttribs")->Set(pRandomAttrsCB); Under the hood, the engine pre-allocates descriptor tables for static and mutable resources when an SRB objcet is created. Space for dynamic resources is dynamically allocated at run time. Static and mutable resources are thus more efficient and should be used whenever possible.
As you can see, Diligent Engine does not expose low-level details of how resources are bound to shader variables. One reason for this is that these details are very different for various APIs. The other reason is that using low-level binding methods is extremely error-prone: it is very easy to forget to bind some resource, or bind incorrect resource such as bind a buffer to the variable that is in fact a texture, especially during shader development when everything changes fast. Diligent Engine instead relies on shader reflection system to automatically query the list of all shader variables. Grouping variables based on three types mentioned above allows the engine to create optimized layout and take heavy lifting of matching resources to API-specific resource location, register or descriptor in the table.
This post gives more details about the resource binding model in Diligent Engine.
Setting the Pipeline State and Committing Shader Resources
Before any draw or compute command can be invoked, the pipeline state needs to be bound to the context:
m_pContext->SetPipelineState(m_pPSO); Under the hood, the engine sets the internal PSO object in the command list or calls all the required native API functions to properly configure all pipeline stages.
The next step is to bind all required shader resources to the GPU pipeline, which is accomplished by IDeviceContext::CommitShaderResources() method:
m_pContext->CommitShaderResources(m_pSRB, COMMIT_SHADER_RESOURCES_FLAG_TRANSITION_RESOURCES); The method takes a pointer to the shader resource binding object and makes all resources the object holds available for the shaders. In the case of D3D12, this only requires setting appropriate descriptor tables in the command list. For older APIs, this typically requires setting all resources individually.
Next-generation APIs require the application to track the state of every resource and explicitly inform the system about all state transitions. For instance, if a texture was used as render target before, while the next draw command is going to use it as shader resource, a transition barrier needs to be executed. Diligent Engine does the heavy lifting of state tracking.  When CommitShaderResources() method is called with COMMIT_SHADER_RESOURCES_FLAG_TRANSITION_RESOURCES flag, the engine commits and transitions resources to correct states at the same time. Note that transitioning resources does introduce some overhead. The engine tracks state of every resource and it will not issue the barrier if the state is already correct. But checking resource state is an overhead that can sometimes be avoided. The engine provides IDeviceContext::TransitionShaderResources() method that only transitions resources:
m_pContext->TransitionShaderResources(m_pPSO, m_pSRB); In some scenarios it is more efficient to transition resources once and then only commit them.
Invoking Draw Command
The final step is to set states that are not part of the PSO, such as render targets, vertex and index buffers. Diligent Engine uses Direct3D11-syle API that is translated to other native API calls under the hood:
ITextureView *pRTVs[] = {m_pRTV}; m_pContext->SetRenderTargets(_countof( pRTVs ), pRTVs, m_pDSV); // Clear render target and depth buffer const float zero[4] = {0, 0, 0, 0}; m_pContext->ClearRenderTarget(nullptr, zero); m_pContext->ClearDepthStencil(nullptr, CLEAR_DEPTH_FLAG, 1.f); // 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); Different native APIs use various set of function to execute draw commands depending on command details (if the command is indexed, instanced or both, what offsets in the source buffers are used etc.). For instance, there are 5 draw commands in Direct3D11 and more than 9 commands in OpenGL with something like glDrawElementsInstancedBaseVertexBaseInstance not uncommon. Diligent Engine hides all details with single IDeviceContext::Draw() method that takes 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); For compute commands, there is IDeviceContext::DispatchCompute() method that takes DispatchComputeAttribs structure that defines compute grid dimension.
Source Code
Full engine source code is available on GitHub and is free to use. The repository contains two samples, asteroids performance benchmark and example Unity project that uses Diligent Engine in native plugin.
AntTweakBar sample is Diligent Engine’s “Hello World” example.

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 multiple render targets, using compute shaders and unordered access views, etc.

Asteroids performance benchmark is based on this demo developed by Intel. It renders 50,000 unique textured asteroids and allows comparing performance of Direct3D11 and Direct3D12 implementations. Every asteroid is a combination of one of 1000 unique meshes and one of 10 unique textures.

Finally, there is an example project that shows how Diligent Engine can be integrated with Unity.

Future Work
The engine is under active development. It currently supports Windows desktop, Universal Windows and Android platforms. Direct3D11, Direct3D12, OpenGL/GLES backends are now feature complete. Vulkan backend is coming next, and support for more platforms is planned.
• By reenigne
For those that don't know me. I am the individual who's two videos are listed here under setup for https://wiki.libsdl.org/Tutorials
I also run grhmedia.com where I host the projects and code for the tutorials I have online.
Recently, I received a notice from youtube they will be implementing their new policy in protecting video content as of which I won't be monetized till I meat there required number of viewers and views each month.

Frankly, I'm pretty sick of youtube. I put up a video and someone else learns from it and puts up another video and because of the way youtube does their placement they end up with more views.
Even guys that clearly post false information such as one individual who said GLEW 2.0 was broken because he didn't know how to compile it. He in short didn't know how to modify the script he used because he didn't understand make files and how the requirements of the compiler and library changes needed some different flags.

At the end of the month when they implement this I will take down the content and host on my own server purely and it will be a paid system and or patreon.

I get my videos may be a bit dry, I generally figure people are there to learn how to do something and I rather not waste their time.
I used to also help people for free even those coming from the other videos. That won't be the case any more. I used to just take anyone emails and work with them my email is posted on the site.

I don't expect to get the required number of subscribers in that time or increased views. Even if I did well it wouldn't take care of each reoccurring month.
I figure this is simpler and I don't plan on putting some sort of exorbitant fee for a monthly subscription or the like.
I was thinking on the lines of a few dollars 1,2, and 3 and the larger subscription gets you assistance with the content in the tutorials if needed that month.
Maybe another fee if it is related but not directly in the content.
The fees would serve to cut down on the number of people who ask for help and maybe encourage some of the people to actually pay attention to what is said rather than do their own thing. That actually turns out to be 90% of the issues. I spent 6 hours helping one individual last week I must have asked him 20 times did you do exactly like I said in the video even pointed directly to the section. When he finally sent me a copy of the what he entered I knew then and there he had not. I circled it and I pointed out that wasn't what I said to do in the video. I didn't tell him what was wrong and how I knew that way he would go back and actually follow what it said to do. He then reported it worked. Yea, no kidding following directions works. But hey isn't alone and well its part of the learning process.

So the point of this isn't to be a gripe session. I'm just looking for a bit of feed back. Do you think the fees are unreasonable?
Should I keep the youtube channel and do just the fees with patreon or do you think locking the content to my site and require a subscription is an idea.

I'm just looking at the fact it is unrealistic to think youtube/google will actually get stuff right or that youtube viewers will actually bother to start looking for more accurate videos.

• i got error 1282 in my code.
#version 450 core layout(location=0) in vec3 inPos; layout(location=1) in vec2 inTexCoord; out vec2 TexCoord; void main() { gl_Position=vec4(inPos,1.0); TexCoord=inTexCoord; } and the fragment shader
#version 450 core in vec2 TexCoord; uniform sampler2D inTextureOne; uniform sampler2D inTextureTwo; out vec4 FragmentColor; void main() { FragmentColor=mix(texture(inTextureOne,TexCoord),texture(inTextureTwo,TexCoord),0.2); } I was expecting awesomeface.png on top of container.jpg