path: root/LibOVR/Src/CAPI/GL/CAPI_GL_HSWDisplay.cpp

/************************************************************************************

Filename    :   CAPI_GL_HSWDisplay.cpp
Content     :   Implements Health and Safety Warning system.
Created     :   July 7, 2014
Authors     :   Paul Pedriana

Copyright   :   Copyright 2014 Oculus VR, Inc. All Rights reserved.

Licensed under the Oculus VR Rift SDK License Version 3.1 (the "License"); 
you may not use the Oculus VR Rift SDK except in compliance with the License, 
which is provided at the time of installation or download, or which 
otherwise accompanies this software in either electronic or hard copy form.

You may obtain a copy of the License at

http://www.oculusvr.com/licenses/LICENSE-3.1 

Unless required by applicable law or agreed to in writing, the Oculus VR SDK 
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

************************************************************************************/


#include "CAPI_GL_HSWDisplay.h"
#include "CAPI_GL_DistortionShaders.h"
#include "../../OVR_CAPI_GL.h"
#include "../../Kernel/OVR_File.h"
#include "../../Kernel/OVR_Math.h"
#include "../../Kernel/OVR_Allocator.h"
#include "../../Kernel/OVR_Color.h"

#include "../Textures/healthAndSafety.tga.h"

OVR_DISABLE_MSVC_WARNING(4996) // "This function or variable may be unsafe..."


namespace OVR { namespace CAPI { 


// Loads the TGA data from the File as an array of width * height 32 bit Texture_RGBA values.
// Returned pointer must be freed with OVR_FREE.
uint8_t* LoadTextureTgaData(OVR::File* f, uint8_t alpha, int& width, int& height)
{
    // See http://www.fileformat.info/format/tga/egff.htm for format details.
    // The TGA file must be exported with compression disabled and with the origin set to the top-left.
    // To do: Support at least RLE formats.
    // TGA files are stored with little-endian data.
    uint8_t* pRGBA  = NULL;

    f->SeekToBegin();
    
    const int desclen = f->ReadUByte();
    const int palette = f->ReadUByte();
    OVR_UNUSED(palette);
    const int imgtype = f->ReadUByte();
    f->ReadUInt16(); // Skip bytes
    int palCount = f->ReadUInt16();
    int palSize = f->ReadUByte();
    f->ReadUInt16();
    f->ReadUInt16();
    width = f->ReadUInt16();
    height = f->ReadUInt16();
    int bpp = f->ReadUByte();
    f->ReadUByte();

    OVR_ASSERT((imgtype == 2) && ((bpp == 24) || (bpp == 32)));

    if((imgtype == 2) && ((bpp == 24) || (bpp == 32)))
    {
        int imgsize = width * height * 4;
        pRGBA = (uint8_t*) OVR_ALLOC(imgsize);
        f->Skip(desclen);
        f->Skip(palCount * (palSize + 7) >> 3);
        int strideBytes = width * 4; // This is the number of bytes between successive rows.


        unsigned char buf[16];

        switch (imgtype)
        {
        case 2: // uncompressed true-color image -- the only image type we support.
            switch (bpp)
            {
            case 24:
                for (int y = 0; y < height; y++)
                {
                    for (int x = 0; x < width; x++)
                    {
                        f->Read(buf, 3); // Data is stored as B, G, R
                        pRGBA[y*strideBytes + x*4 + 0] = buf[2];
                        pRGBA[y*strideBytes + x*4 + 1] = buf[1];
                        pRGBA[y*strideBytes + x*4 + 2] = buf[0];
                        pRGBA[y*strideBytes + x*4 + 3] = alpha;
                    }
                }
                break;
            case 32:
                for (int y = 0; y < height; y++)
                {
                    for (int x = 0; x < width; x++)
                    {
                        f->Read(buf, 4); // Data is stored as B, G, R, A
                        pRGBA[y*strideBytes + x*4 + 0] = buf[2];
                        pRGBA[y*strideBytes + x*4 + 1] = buf[1];
                        pRGBA[y*strideBytes + x*4 + 2] = buf[0];
                        pRGBA[y*strideBytes + x*4 + 3] = buf[3];
                    }
                }
                break;
            }
            break;
        }
    }

    return pRGBA;
} // LoadTextureTgaData



namespace GL {


// To do: This needs to be promoted to a central version, possibly in CAPI_HSWDisplay.h
struct HASWVertex
{
    Vector3f  Pos;
    Color     C;
    float     U, V;    

    HASWVertex(const Vector3f& p, const Color& c = Color(64,0,0,255), float u = 0, float v = 0)
        : Pos(p), C(c), U(u), V(v)
    {}

    HASWVertex(float x, float y, float z, const Color& c = Color(64,0,0,255), float u = 0, float v = 0) 
        : Pos(x,y,z), C(c), U(u), V(v)
    {}

    bool operator==(const HASWVertex& b) const
    {
        return (Pos == b.Pos) && (C == b.C) && (U == b.U) && (V == b.V);
    }
};



// This is a temporary function implementation, and it functionality needs to be implemented in a more generic way.
Texture* LoadTextureTga(RenderParams& rParams, int samplerMode, OVR::File* f, uint8_t alpha)
{
    OVR::CAPI::GL::Texture* pTexture = NULL;

    int width, height;
    const uint8_t* pRGBA = LoadTextureTgaData(f, alpha, width, height);

    if (pRGBA)
    {
        pTexture = new OVR::CAPI::GL::Texture(&rParams, width, height);

        // SetSampleMode forces the use of mipmaps through GL_LINEAR_MIPMAP_LINEAR.
        pTexture->SetSampleMode(samplerMode); // Calls glBindTexture internally.

        // We are intentionally not using mipmaps. We need to use this because Texture::SetSampleMode unilaterally uses GL_LINEAR_MIPMAP_LINEAR.
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0);

        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, pRGBA);
        OVR_ASSERT(glGetError() == 0);

        // With OpenGL 4.2+ we can use this instead of glTexImage2D:
        // glTexStorage2D(GL_TEXTURE_2D, 1, GL_RGBA8, width, height);
        // glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, pRGBA);

        OVR_FREE(const_cast<uint8_t*>(pRGBA));
    }

    return pTexture;
}


// Loads a texture from a memory image of a TGA file.
Texture* LoadTextureTga(RenderParams& rParams, int samplerMode, const uint8_t* pData, int dataSize, uint8_t alpha)
{
    MemoryFile memoryFile("", pData, dataSize);

    return LoadTextureTga(rParams, samplerMode, &memoryFile, alpha);
}




// The texture below may conceivably be shared between HSWDisplay instances. However,  
// beware that sharing may not be possible if two HMDs are using different locales  
// simultaneously. As of this writing it's not clear if that can occur in practice.

HSWDisplay::HSWDisplay(ovrRenderAPIType api, ovrHmd hmd, const HMDRenderState& renderState)
  : OVR::CAPI::HSWDisplay(api, hmd, renderState),
    RenderParams(),
    FrameBuffer(0)
{
}
    
bool HSWDisplay::Initialize(const ovrRenderAPIConfig* apiConfig)
{
    const ovrGLConfig* config = (const ovrGLConfig*)apiConfig;

    if(config)
    {
        // The following is essentially copied from CAPI_GL_DistortionRender.cpp's 
        // Initialize function. To do: Merge this to a central location.
        RenderParams.Multisample = config->OGL.Header.Multisample;
        RenderParams.RTSize      = config->OGL.Header.RTSize;

        #if defined(OVR_OS_WIN32)
            RenderParams.Window = (config->OGL.Window) ? config->OGL.Window : GetActiveWindow();
            RenderParams.DC     = config->OGL.DC;
        #elif defined(OVR_OS_LINUX)
            if (config->OGL.Disp)
                RenderParams.Disp = config->OGL.Disp;
            if (!RenderParams.Disp)
                RenderParams.Disp = XOpenDisplay(NULL);
            if (!RenderParams.Disp)
            {
                OVR_DEBUG_LOG(("XOpenDisplay failed."));
                return false;
            }

            if (config->OGL.Win)
                RenderParams.Win= config->OGL.Win;
            if (!RenderParams.Win)
            {
                int unused;
                RenderParams.Win = glXGetCurrentDrawable();
            }
            if (!RenderParams.Win)
            {
                OVR_DEBUG_LOG(("XGetInputFocus failed."));
                return false;
            }
        #endif
    }
    else
    {
        UnloadGraphics();
    }

    return true;
}


void HSWDisplay::Shutdown()
{
    UnloadGraphics();
}


void HSWDisplay::DisplayInternal()
{
    HSWDISPLAY_LOG(("[HSWDisplay GL] DisplayInternal()"));
    // We may want to call LoadGraphics here instead of within Render.
}


void HSWDisplay::DismissInternal()
{
    HSWDISPLAY_LOG(("[HSWDisplay GL] DismissInternal()"));
    UnloadGraphics();
}


void HSWDisplay::UnloadGraphics()
{
    // RenderParams: No need to clear.
    if(FrameBuffer != 0)
    {
        glDeleteFramebuffers(1, &FrameBuffer);
        FrameBuffer = 0;
    }
    pTexture.Clear();
    pShaderSet.Clear();
    pVertexShader.Clear();
    pFragmentShader.Clear();
    pVB.Clear();
    // OrthoProjection: No need to clear.
}


void HSWDisplay::LoadGraphics()
{
    int glVersionMajor = 0;
    int glVersionMinor = 0;
    const char* glVersionString = (const char*)glGetString(GL_VERSION);

    OVR_ASSERT(glVersionString);
    if (glVersionString)
    {
        int fieldCount = sscanf(glVersionString, isdigit(*glVersionString) ? "%d.%d" : "%*[^0-9]%d.%d", &glVersionMajor, &glVersionMinor); // Skip all leading non-digits before reading %d. Example glVersionStrings: "1.5 ATI-1.4.18", "OpenGL ES-CM 3.2"
        
        if(fieldCount != 2)
        {
            static_assert(sizeof(glVersionMajor) == sizeof(GLint), "type mis-match");
            glGetIntegerv(GL_MAJOR_VERSION, &glVersionMajor);
        }
    }

    if (FrameBuffer == 0)
        glGenFramebuffers(1, &FrameBuffer);

    if (!pTexture) // To do: Add support for .dds files, which would be significantly smaller than the size of the tga.
        pTexture = *LoadTextureTga(RenderParams, Sample_Linear | Sample_Clamp, healthAndSafety_tga, (int)sizeof(healthAndSafety_tga), 255);

    if(!pShaderSet)
        pShaderSet = *new ShaderSet();

    if(!pVertexShader)
    {
        OVR::String strShader((glVersionMajor >= 3) ? glsl3Prefix : glsl2Prefix);
        strShader += SimpleTexturedQuad_vs;

        pVertexShader = *new VertexShader(&RenderParams, const_cast<char*>(strShader.ToCStr()), strShader.GetLength(), SimpleTexturedQuad_vs_refl, OVR_ARRAY_COUNT(SimpleTexturedQuad_vs_refl));
        pShaderSet->SetShader(pVertexShader);
    }

    if(!pFragmentShader)
    {
        OVR::String strShader((glVersionMajor >= 3) ? glsl3Prefix : glsl2Prefix);
        strShader += SimpleTexturedQuad_ps;

        pFragmentShader = *new FragmentShader(&RenderParams, const_cast<char*>(strShader.ToCStr()), strShader.GetLength(), SimpleTexturedQuad_ps_refl, OVR_ARRAY_COUNT(SimpleTexturedQuad_ps_refl));
        pShaderSet->SetShader(pFragmentShader);
    }

    if(!pVB)
    {
        pVB = *new Buffer(&RenderParams);

        pVB->Data(Buffer_Vertex, NULL, 4 * sizeof(HASWVertex));
        HASWVertex* pVertices = (HASWVertex*)pVB->Map(0, 4 * sizeof(HASWVertex), Map_Discard);
        OVR_ASSERT(pVertices);

        if(pVertices)
        {
            const bool  flip   = ((RenderState.DistortionCaps & ovrDistortionCap_FlipInput) != 0);
            const float left   = -1.0f; // We currently draw this in normalized device coordinates with an stereo translation
            const float top    = -1.1f; // applied as a vertex shader uniform. In the future when we have a more formal graphics
            const float right  =  1.0f; // API abstraction we may move this draw to an overlay layer or to a more formal 
            const float bottom =  0.9f; // model/mesh scheme with a perspective projection.

            pVertices[0] = HASWVertex(left,  top,    0.f, Color(255, 255, 255, 255), 0.f, flip ? 1.f : 0.f); // To do: Make this branchless 
            pVertices[1] = HASWVertex(left,  bottom, 0.f, Color(255, 255, 255, 255), 0.f, flip ? 0.f : 1.f);
            pVertices[2] = HASWVertex(right, top,    0.f, Color(255, 255, 255, 255), 1.f, flip ? 1.f : 0.f); 
            pVertices[3] = HASWVertex(right, bottom, 0.f, Color(255, 255, 255, 255), 1.f, flip ? 0.f : 1.f);

            pVB->Unmap(pVertices);
        }
    }

    // Calculate ortho projection.
    GetOrthoProjection(RenderState, OrthoProjection);
}


void HSWDisplay::RenderInternal(ovrEyeType eye, const ovrTexture* eyeTexture)
{
    if(RenderEnabled && eyeTexture)
    {
        // We need to render to the eyeTexture with the texture viewport.
        // Setup rendering to the texture.
        ovrGLTexture* eyeTextureGL = const_cast<ovrGLTexture*>(reinterpret_cast<const ovrGLTexture*>(eyeTexture));
        OVR_ASSERT(eyeTextureGL->Texture.Header.API == ovrRenderAPI_OpenGL);

        // Load the graphics if not loaded already.
        if (!pTexture)
            LoadGraphics();

        // Set the rendering to be to the eye texture.
        glBindFramebuffer(GL_FRAMEBUFFER, FrameBuffer);
        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, eyeTextureGL->OGL.TexId, 0);
        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, 0); // We aren't using depth, as we currently want this to overwrite everything.
        // GLenum DrawBuffers[1] = { GL_COLOR_ATTACHMENT0 };
        // glDrawBuffers(OVR_ARRAY_COUNT(DrawBuffers), DrawBuffers);
        GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
        OVR_ASSERT(status == GL_FRAMEBUFFER_COMPLETE); OVR_UNUSED(status);

        // Set up the viewport
        const GLint   x = (GLint)eyeTextureGL->Texture.Header.RenderViewport.Pos.x;
        const GLint   y = (GLint)eyeTextureGL->Texture.Header.RenderViewport.Pos.y; // Note that GL uses bottom-up coordinates.
        const GLsizei w = (GLsizei)eyeTextureGL->Texture.Header.RenderViewport.Size.w;
        const GLsizei h = (GLsizei)eyeTextureGL->Texture.Header.RenderViewport.Size.h;
        glViewport(x, y, w, h);

        // Set fixed-function render states
        glDisable(GL_DEPTH_TEST);
        glEnable(GL_CULL_FACE);  // Irrelevant to our case here.
        glFrontFace(GL_CW);
        glEnable(GL_BLEND);
        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
        OVR_ASSERT(glGetError() == 0);

        // Enable the buffer and shaders we use.
        glBindBuffer(GL_ARRAY_BUFFER, pVB->GLBuffer);
        OVR_ASSERT(glGetError() == 0);

        ShaderFill fill(pShaderSet);
        if(pTexture)
        {
            fill.SetTexture(0, pTexture);
            OVR_ASSERT(glGetError() == 0);
        }

        // Set shader uniforms.
        const float scale  = HSWDISPLAY_SCALE * ((RenderState.OurHMDInfo.HmdType == HmdType_DK1) ? 0.70f : 1.f);
        pShaderSet->SetUniform2f("Scale", scale, scale / 2.f); // X and Y scale. Y is a fixed proportion to X in order to give a certain aspect ratio.
        pShaderSet->SetUniform2f("PositionOffset", OrthoProjection[eye].GetTranslation().x, 0.0f);
        OVR_ASSERT(glGetError() == 0);

        // Set vertex attributes
        // To consider: We can use glGenVertexArrays + glBindVertexArray here to tell GL to store the attrib values below in 
        // a vertex array object so later we can simply call glBindVertexArray(VertexArrayObject) to enable them instead 
        // of doing all the calls below again. glBindVertexArray(0) to unbind, glDeleteVertexArrays to destory. Requires 
        // OpenGL v3+ or the GL_ARB_vertex_array_object extension.

        const GLuint shaderProgram = pShaderSet->Prog;
        int attributeLocationArray[3];

        attributeLocationArray[0] = glGetAttribLocation(shaderProgram, "Position");
        glVertexAttribPointer(attributeLocationArray[0], sizeof(Vector3f)/sizeof(float), GL_FLOAT,         false, sizeof(HASWVertex), reinterpret_cast<char*>(offsetof(HASWVertex, Pos)));

        attributeLocationArray[1] = glGetAttribLocation(shaderProgram, "Color");
        glVertexAttribPointer(attributeLocationArray[1], sizeof(Color)/sizeof(uint8_t),  GL_UNSIGNED_BYTE, false, sizeof(HASWVertex), reinterpret_cast<char*>(offsetof(HASWVertex, C)));

        attributeLocationArray[2] = glGetAttribLocation(shaderProgram, "TexCoord");
        glVertexAttribPointer(attributeLocationArray[2], sizeof(float[2])/sizeof(float), GL_FLOAT,         false, sizeof(HASWVertex), reinterpret_cast<char*>(offsetof(HASWVertex, U)));

        for (size_t i = 0; i < OVR_ARRAY_COUNT(attributeLocationArray); i++)
            glEnableVertexAttribArray((GLuint)i);
        OVR_ASSERT(glGetError() == 0);

        fill.Set(Prim_TriangleStrip);
        OVR_ASSERT(glGetError() == 0);

        glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
        OVR_ASSERT(glGetError() == 0);

        for (size_t i = 0; i < OVR_ARRAY_COUNT(attributeLocationArray); i++)
            glDisableVertexAttribArray(i);
    }
}
 

}}} // namespace OVR::CAPI::GL