/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "WebGL2Context.h"
#include "WebGLActiveInfo.h"
#include "WebGLProgram.h"
#include "WebGLTransformFeedback.h"
#include "GLContext.h"

namespace mozilla {

// -------------------------------------------------------------------------
// Transform Feedback

already_AddRefed<WebGLTransformFeedback>
WebGL2Context::CreateTransformFeedback()
{
    if (IsContextLost())
        return nullptr;

    GLuint tf = 0;
    MakeContextCurrent();
    gl->fGenTransformFeedbacks(1, &tf);

    nsRefPtr<WebGLTransformFeedback> globj = new WebGLTransformFeedback(this, tf);
    return globj.forget();
}

void
WebGL2Context::DeleteTransformFeedback(WebGLTransformFeedback* tf)
{
    if (IsContextLost())
        return;

    if (!ValidateObjectAllowDeletedOrNull("deleteTransformFeedback", tf))
        return;

    if (!tf || tf->IsDeleted())
        return;

    if (mBoundTransformFeedback == tf)
        BindTransformFeedback(LOCAL_GL_TRANSFORM_FEEDBACK, tf);

    tf->RequestDelete();
}

bool
WebGL2Context::IsTransformFeedback(WebGLTransformFeedback* tf)
{
    if (IsContextLost())
        return false;

    if (!ValidateObjectAllowDeleted("isTransformFeedback", tf))
        return false;

    if (tf->IsDeleted())
        return false;

    MakeContextCurrent();
    return gl->fIsTransformFeedback(tf->mGLName);
}

void
WebGL2Context::BindTransformFeedback(GLenum target, WebGLTransformFeedback* tf)
{
    if (IsContextLost())
        return;

    if (!ValidateObjectAllowDeletedOrNull("bindTransformFeedback", tf))
        return;

    if (target != LOCAL_GL_TRANSFORM_FEEDBACK)
        return ErrorInvalidEnum("bindTransformFeedback: target must be TRANSFORM_FEEDBACK");

    WebGLRefPtr<WebGLTransformFeedback> currentTF = mBoundTransformFeedback;
    if (currentTF && currentTF->mIsActive && !currentTF->mIsPaused) {
        return ErrorInvalidOperation("bindTransformFeedback: Currently bound transform "
                                     "feedback is active and not paused");
    }

    if (tf && tf->IsDeleted())
        return ErrorInvalidOperation("bindTransformFeedback: Attempt to bind deleted id");

    MakeContextCurrent();
    gl->fBindTransformFeedback(target, tf ? tf->mGLName : 0);
    if (tf)
        mBoundTransformFeedback = tf;
    else
        mBoundTransformFeedback = mDefaultTransformFeedback;
}

void
WebGL2Context::BeginTransformFeedback(GLenum primitiveMode)
{
    if (IsContextLost())
        return;

    WebGLTransformFeedback* tf = mBoundTransformFeedback;
    MOZ_ASSERT(tf);
    if (!tf)
        return;

    if (tf->mIsActive)
        return ErrorInvalidOperation("beginTransformFeedback: transform feedback is active");

    const GLenum mode = tf->mMode;
    if (mode != LOCAL_GL_POINTS && mode != LOCAL_GL_LINES && mode != LOCAL_GL_TRIANGLES)
        return ErrorInvalidEnum("beginTransformFeedback: primitive must be one of POINTS, LINES, or TRIANGLES");

    // TODO:
    // GL_INVALID_OPERATION is generated by glBeginTransformFeedback
    // if any binding point used in transform feedback mode does not
    // have a buffer object bound. In interleaved mode, only the first
    // buffer object binding point is ever written to.

    // GL_INVALID_OPERATION is generated by glBeginTransformFeedback
    // if no binding points would be used, either because no program
    // object is active of because the active program object has
    // specified no varying variables to record.
    if (!mCurrentProgram)
        return ErrorInvalidOperation("beginTransformFeedback: no program is active");

    MakeContextCurrent();
    gl->fBeginTransformFeedback(primitiveMode);
    tf->mIsActive = true;
    tf->mIsPaused = false;
}

void
WebGL2Context::EndTransformFeedback()
{
    if (IsContextLost())
        return;

    WebGLTransformFeedback* tf = mBoundTransformFeedback;
    MOZ_ASSERT(tf);

    if (!tf)
        return;

    if (!tf->mIsActive)
        return ErrorInvalidOperation("%s: transform feedback in not active",
                                     "endTransformFeedback");

    MakeContextCurrent();
    gl->fEndTransformFeedback();
    tf->mIsActive = false;
    tf->mIsPaused = false;
}

void
WebGL2Context::PauseTransformFeedback()
{
    if (IsContextLost())
        return;

    WebGLTransformFeedback* tf = mBoundTransformFeedback;
    MOZ_ASSERT(tf);
    if (!tf)
        return;

    if (!tf->mIsActive || tf->mIsPaused) {
        return ErrorInvalidOperation("%s: transform feedback is not active or is paused",
                                     "pauseTransformFeedback");
    }

    MakeContextCurrent();
    gl->fPauseTransformFeedback();
    tf->mIsPaused = true;
}

void
WebGL2Context::ResumeTransformFeedback()
{
    if (IsContextLost())
        return;

    WebGLTransformFeedback* tf = mBoundTransformFeedback;
    MOZ_ASSERT(tf);
    if (!tf)
        return;

    if (!tf->mIsActive || !tf->mIsPaused)
        return ErrorInvalidOperation("resumeTransformFeedback: transform feedback is not active or is not paused");

    MakeContextCurrent();
    gl->fResumeTransformFeedback();
    tf->mIsPaused = false;
}

void
WebGL2Context::TransformFeedbackVaryings(WebGLProgram* program,
                                         const dom::Sequence<nsString>& varyings,
                                         GLenum bufferMode)
{
    if (IsContextLost())
        return;

    if (!ValidateObject("transformFeedbackVaryings: program", program))
        return;

    program->TransformFeedbackVaryings(varyings, bufferMode);
}

already_AddRefed<WebGLActiveInfo>
WebGL2Context::GetTransformFeedbackVarying(WebGLProgram* program, GLuint index)
{
    if (IsContextLost())
        return nullptr;

    if (!ValidateObject("getTransformFeedbackVarying: program", program))
        return nullptr;

    return program->GetTransformFeedbackVarying(index);
}

} // namespace mozilla
