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Mip mapping issue

OpenGL

Started by Wilhelm van Huyssteen Sep 11, 2014 at 5:10 PM 8 replies 2.2k views

Original Post

Wilhelm van Huyssteen

232

Wilhelm van Huyssteen

Sep 11, 2014 at 5:10 PM

Hi.

I am busy writing a directx renderer for my engine that up until now was opengl only. Here is a screenshot rendered in opengl that demonstrates what Im trying to achieve.

Here is the same scene rendered in directx

Looking at the far away terrain the mipmapping in the directx version seems a bit of (well I think its the mipmapping). You can clearly see some ugly patterns forming the further you go.

The only only difference between the 2 (that i can think of) is the way the mip maps are generated. In the opengl one the mipmaps are created using gluBuild2DMipmaps. In the direcx one I generate the mipmaps myself and i simply average the nearest 4 pixels together when downscaling. So my first thought was that gluBuild2DMipmaps uses a different algorithm to downscale the image but I cant seem to find more information on it. Maybe the problem is something else entirely? Either way any help will appreciated.

Thnx in Advance!

Samith

305

Samith

Sep 11, 2014 at 5:29 PM

Since gluBuild2DMipmaps is more of a utility function to get things running than a final solution, I would be surprised if it was doing anything more complicated than a simple box filter (like what you're doing in your DirectX version right now).

However, you can rule out gluBuild2DMipmaps as the source of your problem by simply doing the same thing you do in DirectX in OpenGL. Have you tried generating mips yourself in OpenGL, the same way you do in DirectX, and seeing if that produces results that look the same?

Also, are you sure your DirectX mip map generation is correct? Have you looked at the generated mips directly and verified that they're correct? It can be kind of hard to tell just from an in-game screenshot whether the mips are exactly right (or exactly what you're expecting, since "right" is kind of subjective).

kauna

Sep 11, 2014 at 5:33 PM

Which texture filter mode are you using when rendering?

Cheers!

satanir

Sep 11, 2014 at 5:37 PM

Can you provide the code that shows how you generate and use the texture?

Why aren't you using DirectX functions (When creating the resource or with GenerateMipMaps)?

Also, make sure you're rendering state is correct - you didn't specify which DX version you are using, but it can be due to incorrect ShaderResourceView::MipLevels and SamplerState::MaxLod fields.

21st Century Moose

395

21st Century Moose

Sep 11, 2014 at 9:07 PM

GenerateMips is only valid if the base resource is created with D3D11_BIND_RENDER_TARGET (you don't say which D3D version you're using here so I'm assuming 11).

Per-spec, gluBuild2DMipmaps uses a box filter, which is exactly what you say you're using for your D3D code, so the error may be in your box filter code.

What I'd advise you check first, however, is your D3D sampler states. The min/mag/mip filtering modes work quite differently in D3D than they do in GL, with sampler states being decoupled from the textures rather than being part of a texture object, so this is one likely source of error: I consider it at least possible that this is wrong and you've ended up with a nearest filter where you probably want min/map/mip linear.

(Yes, later versions of GL have sampler objects too, but I'm assuming - from mention of gluBuild2DMapmaps - that the OP is using an earlier version.)

Wilhelm van Huyssteen

Author

232

Wilhelm van Huyssteen

Sep 12, 2014 at 12:32 AM

Ok.

I use directX 11. And yes the opengl is quite a bit older.

filter options in opengl:

[source]

GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MIN_FILTER, GL11.GL_LINEAR_MIPMAP_LINEAR);

GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MAG_FILTER, GL11.GL_LINEAR);

[/source]

filter options in directx

[source]

D3D11_SAMPLER_DESC sampDesc;

ZeroMemory(&sampDesc, sizeof(sampDesc));

sampDesc.Filter = D3D11_FILTER_MIN_MAG_MIP_LINEAR;

sampDesc.AddressU = D3D11_TEXTURE_ADDRESS_WRAP;

sampDesc.AddressV = D3D11_TEXTURE_ADDRESS_WRAP;

sampDesc.AddressW = D3D11_TEXTURE_ADDRESS_WRAP;

sampDesc.ComparisonFunc = D3D11_COMPARISON_NEVER;

sampDesc.MinLOD = 0;

sampDesc.MaxLOD = D3D11_FLOAT32_MAX;

[/source]

Shaders. The first 4 textures contain height, normal and tile weight information. the next 8 textures are the actual colour textures for the terrain. all textures and samplers are bound to the vertex and pixel shader using the same slots (for compatibility with opengl). The pixel shader contains 1 sampler for each texture but theyre all the same. The vertex shader is probaly pretty irrelevent to the question.

vertex shader

[source]

Texture2D tex1 : register( t0 );

SamplerState samp1 : register( s0 );

Texture2D tex2 : register( t1 );

SamplerState samp2 : register( s1 );

Texture2D tex3 : register( t2 );

SamplerState samp3 : register( s2 );

Texture2D tex4 : register( t3 );

SamplerState samp4 : register( s3 );

struct VSInput

{

float4 pos : a_position;

float2 textCoordA : v_textCoordA;

};

struct PSInput

{

float4 pos : SV_Position;

float3 p : v_pos;

float2 textCoordA : v_textCoordA;

float3 normal : v_normal;

float2 gridPos : v_gridPos;

float w1 : v_w1;

float w2 : v_w2;

float w3 : v_w3;

float w4 : v_w4;

float w5 : v_w5;

float w6 : v_w6;

float w7 : v_w7;

float w8 : v_w8;

float2 c : v_c;

};

PSInput main(VSInput attrib)

{

PSInput ps;

float4 vpos = attrib.pos;

ps.gridPos = float2(vpos.x*128,vpos.y*128);

float2 coord = float2(vpos.x/(8*lod)+tOffset.x,vpos.y/(8*lod)+tOffset.y);

ps.c = coord;

coord.x = clamp(coord.x,1.0/1024.0,1023.0/1024.0);

coord.y = clamp(coord.y,1.0/1024.0,1023.0/1024.0);

coord = float2(coord.x+1.0/2048, coord.y+1.0/2048);

float2 ic = float2(vpos.x/(8*lod)+tOffset.x,vpos.y/(8*lod)+tOffset.y);

ic = ic * 1024;

ic.x = clamp(ic.x,1.0,1023.0);

ic.y = clamp(ic.y,1.0,1023.0);

uint3 ici = uint3(ic.x,ic.y,0);

float4 t1 = tex1.Load(ici);

float4 t2 = tex2.Load(ici);

float4 t3 = tex3.Load(ici);

float4 t4 = tex4.Load(ici);

float h = (t1.r-(127.0/255.0)) * 65280.0 +

t1.g * 255.0 +

t1.b * 1.0;

vpos.z = vpos.z + h;

ps.normal = t2.rgb*2-1;

float4 vertPos = mul(vpos,modelMatrix);

ps.pos = mul(vertPos,projectionAndViewMatrix);

ps.p = vertPos.xyz;

ps.w1 = t3.r;

ps.w2 = t3.g;

ps.w3 = t3.b;

ps.w4 = t3.a;

ps.w5 = t4.r;

ps.w6 = t4.g;

ps.w7 = t4.b;

ps.w8 = t4.a;

ps.textCoordA = attrib.textCoordA*(8.0/lod);

return ps;

}

[/source]

Pixel shader

[source]

Texture2D tex1 : register( t0 );

Texture2D tile1 : register( t4 );

Texture2D tile2 : register( t5 );

Texture2D tile3 : register( t6 );

Texture2D tile4 : register( t7 );

Texture2D tile5 : register( t8 );

Texture2D tile6 : register( t9 );

Texture2D tile7 : register( t10 );

Texture2D tile8 : register( t11 );

SamplerState samp1 : register( s4 );

SamplerState samp2 : register( s5 );

SamplerState samp3 : register( s6 );

SamplerState samp4 : register( s7 );

SamplerState samp5 : register( s8 );

SamplerState samp6 : register( s9 );

SamplerState samp7 : register( s10 );

SamplerState samp8 : register( s11 );

struct PSInput

{

float4 pos : SV_Position;

float3 p : v_pos;

float2 textCoordA : v_textCoordA;

float3 normal : v_normal;

float2 gridPos : v_gridPos;

float w1 : v_w1;

float w2 : v_w2;

float w3 : v_w3;

float w4 : v_w4;

float w5 : v_w5;

float w6 : v_w6;

float w7 : v_w7;

float w8 : v_w8;

float2 c : v_c;

};

float4 main(PSInput ps) : SV_Target

{

uint x = int(floor(ps.p.x));

uint y = int(floor(ps.p.y));

x = x % 1024;

y = y % 1024;

float4 t1 = tex1.Load(uint3(ps.c.x*1024,ps.c.y*1024,0));

if (t1.a == 0.0) //indicates a hole in the terrain. Caves etc.

{

discard;

}

float3 n = normalize(ps.normal);

float4 c1 = tile1.Sample(samp1, ps.textCoordA);

float4 c2 = tile2.Sample(samp2, ps.textCoordA);

float4 c3 = tile3.Sample(samp3, ps.textCoordA);

float4 c4 = tile4.Sample(samp4, ps.textCoordA);

float4 c5 = tile5.Sample(samp5, ps.textCoordA);

float4 c6 = tile6.Sample(samp6, ps.textCoordA);

float4 c7 = tile7.Sample(samp7, ps.textCoordA);

float4 c8 = tile8.Sample(samp8, ps.textCoordA);

float4 fvBaseColor = c1;

float total = ps.w1+ps.w2+ps.w3+ps.w4+ps.w5+ps.w6+ps.w7+ps.w8;

if (total > 0.0)

{

fvBaseColor = c1 * ps.w1 + c2 * ps.w2 + c3 * ps.w3 + c4 * ps.w4 + c5 * ps.w5 + c6 * ps.w6 + c7 * ps.w7 + c8 * ps.w8;

fvBaseColor.a = 0.0;

}

float NdotL = max(dot(n, normalize(float3(1000,-1000,1000))),0.0);

float cut = 0.3;

float shade = 0.85;

if (NdotL > cut + 0.05)

{

NdotL = 1.0;

}

else if (NdotL < cut)

{

NdotL = shade;

}

else

{

NdotL = ((NdotL - cut)*20)*(1.0-shade)+shade;

}

NdotL = 1.0 - NdotL;

float4 diffuse = float4(fvBaseColor.r-NdotL,fvBaseColor.g-NdotL,fvBaseColor.b-NdotL,1.0);

float4 colour1 = diffuse;

float len = length(ps.p-camera);

float start = 500.0;

float end = 700.0;

float4 fadeColor = float4(0.3,0.3,0.9,1.0);

if (len > start)

{

if (len > end)

{

colour1 = fadeColor;

}

else

{

colour1 = lerp(colour1,fadeColor,(len-start)/(end-start));

}

float4 cc2 = colour1;

cc2.a = 1.0;

if (death == 1)

{

float grey = (cc2.r+cc2.g+cc2.b)/3.0;

cc2.r = grey;

cc2.g = grey;

cc2.b = grey;

}

return cc2;

}

[/source]

Here is the code that creates the texture. My game engine is written in Java but since you cant do directx in java directly I wrote my directx calls in c++). I create and concatenate all the mip levels in java before calling this c++ method. If the mipLevel is higher than one this method will only work for textures that has width and height values that is multiples of 2 I will improve that as soon as this problem is sorted out. This is probably the part that I'm the most unsure of. especially where I load all the mipmaps into the SUB_RESOURCE_DATA array.

[source]

struct Texture

{

ID3D11ShaderResourceView* textureView;

ID3D11DepthStencilView* depthStencilView;

ID3D11RenderTargetView* renderTargetView;

ID3D11SamplerState* sampler;

};

JNIEXPORT jint JNICALL Java_dmdx11_DmdxNative_createTexture(JNIEnv* env, jobject, jobject data, jint width, jint height, jint type,jint mipLevel)

{

Texture texture = Texture();

ID3D11Texture2D* pTexture;

if (type == 0)//color

{

D3D11_SHADER_RESOURCE_VIEW_DESC shaderResourceViewDesc;

D3D11_RENDER_TARGET_VIEW_DESC renderTargetViewDesc;

D3D11_TEXTURE2D_DESC sTexDesc;

sTexDesc.Width = width;

sTexDesc.Height = height;

sTexDesc.MipLevels = mipLevel;

sTexDesc.ArraySize = 1;

sTexDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;

sTexDesc.SampleDesc.Count = 1;

sTexDesc.SampleDesc.Quality = 0;

sTexDesc.Usage = D3D11_USAGE_IMMUTABLE;

sTexDesc.BindFlags = D3D11_BIND_SHADER_RESOURCE;

sTexDesc.CPUAccessFlags = 0;

sTexDesc.MiscFlags = 0;

D3D11_SUBRESOURCE_DATA *sSubData = new D3D11_SUBRESOURCE_DATA[mipLevel];

int sofar = 0;

for (int i = 0; i < mipLevel; i++)

{

sSubData.pSysMem = (jbyte*)env->GetDirectBufferAddress(data) + sofar;

sSubData.SysMemPitch = (UINT)(width * 4);

sSubData.SysMemSlicePitch = (UINT)(width * height * 4);

sofar += (int)(width * height * 4);

width = width / 2;

height = height / 2;

}

hr = g_pd3dDevice->CreateTexture2D(&sTexDesc, sSubData, &pTexture);

delete[] sSubData;

shaderResourceViewDesc.Format = sTexDesc.Format;

shaderResourceViewDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE2D;

shaderResourceViewDesc.Texture2D.MostDetailedMip = 0;

shaderResourceViewDesc.Texture2D.MipLevels = mipLevel;

g_pd3dDevice->CreateShaderResourceView(pTexture, &shaderResourceViewDesc, &texture.textureView);

D3D11_SAMPLER_DESC sampDesc;

ZeroMemory(&sampDesc, sizeof(sampDesc));

sampDesc.Filter = D3D11_FILTER_MIN_MAG_MIP_LINEAR;

sampDesc.AddressU = D3D11_TEXTURE_ADDRESS_WRAP;

sampDesc.AddressV = D3D11_TEXTURE_ADDRESS_WRAP;

sampDesc.AddressW = D3D11_TEXTURE_ADDRESS_WRAP;

sampDesc.ComparisonFunc = D3D11_COMPARISON_NEVER;

sampDesc.MinLOD = 0;

sampDesc.MaxLOD = D3D11_FLOAT32_MAX;

g_pd3dDevice->CreateSamplerState(&sampDesc, &texture.sampler);

}

...

}

[/source]

If theres any more information needed please ask.

Thank you for your time ^^

21st Century Moose

395

21st Century Moose

Sep 12, 2014 at 9:28 AM

0 isn't a valid value for MaxAnisotropy; it needs to be between 1 and 16: http://msdn.microsoft.com/en-us/library/windows/desktop/ff476207%28v=vs.85%29.aspx

(Note that 1, not 0, is for anisotropic filtering disabled).

I suggest correcting this first, then see if the problems still happen.

21st Century Moose

395

21st Century Moose

Sep 12, 2014 at 10:04 AM

Also, and unrelated to your problem, because sampler states are fully decoupled from textures, you can do this:

float4 c1 = tile1.Sample(samp1, ps.textCoordA);
float4 c2 = tile2.Sample(samp1, ps.textCoordA);
float4 c3 = tile3.Sample(samp1, ps.textCoordA);
float4 c4 = tile4.Sample(samp1, ps.textCoordA);
float4 c5 = tile5.Sample(samp1, ps.textCoordA);
float4 c6 = tile6.Sample(samp1, ps.textCoordA);
float4 c7 = tile7.Sample(samp1, ps.textCoordA);
float4 c8 = tile8.Sample(samp1, ps.textCoordA);

satanir

Sep 12, 2014 at 10:20 AM

0 isn't a valid value for MaxAnisotropy; it needs to be between 1 and 16: http://msdn.microsoft.com/en-us/library/windows/desktop/ff476207%28v=vs.85%29.aspx
(Note that 1, not 0, is for anisotropic filtering disabled).
I suggest correcting this first, then see if the problems still happen.

This value is ignored in case the filter type is not anisotropic.

Appraently, 0 is indeed a valid value even if the filter type is anisotropic.


D3D11 ERROR: ID3D11Device::CreateSamplerState: MaxAnisotropy must be in the range [0 to 16].  20 specified. [ STATE_CREATION ERROR #226: CREATESAMPLERSTATE_INVALIDMAXANISOTROPY]

Wilhelm van Huyssteen

Author

232

Wilhelm van Huyssteen

Sep 12, 2014 at 2:30 PM

So. since mhagain mentioned that gluBuild2DMipmaps uses a box filter as well I went back to my mipmap generation code and I discovered that (as part of some earlier testing/debugging) I commented out the line of code that averages the 4 nearest pixels together and instead replaced it with a line that that just uses the value of the top-left pixel and ignores the rest...

Undoing that bit of test code the directx version now renders perfectly. Feel kind of silly. Should probably take it easy with all the late night coding.

Thank you for your time.

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