/**
** Supermodel
** A Sega Model 3 Arcade Emulator.
** Copyright 2011-2012 Bart Trzynadlowski, Nik Henson
**
** This file is part of Supermodel.
**
** Supermodel is free software: you can redistribute it and/or modify it under
** the terms of the GNU General Public License as published by the Free
** Software Foundation, either version 3 of the License, or (at your option)
** any later version.
**
** Supermodel is distributed in the hope that it will be useful, but WITHOUT
** ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
** FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
** more details.
**
** You should have received a copy of the GNU General Public License along
** with Supermodel. If not, see .
**/
/*
* Render2D.cpp
*
* Implementation of the CRender2D class: OpenGL tile generator graphics.
*
* To-Do List
* ----------
* - Is there a universal solution to the 'ROLLING START' scrolling bug (Scud
* Race) and the scrolling text during Magical Truck Adventure's attract
* mode? To fix Scud Race, either the stencil mask or the h-scroll value must
* be shifted by 16 pixels. Magical Truck Adventure is similar but opposite.
* Perhaps this is a function of timing registers accessed via JTAG?
* - Is there a better way to handle the overscan regions in wide screen mode?
* Is clearing two thin viewports better than one big clear?
* - Are v-scroll values 9 or 10 bits? (Does it matter?) Lost World seems to
* have some scrolling issues.
* - A proper shut-down function is needed! OpenGL might not be available when
* the destructor for this class is called.
*
* Tile Generator Hardware Overview
* --------------------------------
*
* Model 3's medium resolution tile generator hardware appears to be derived
* from the Model 2 and System 24 chipset, but is much simpler. It consists of
* four 64x64 tile layers, comprised of 8x8 pixel tiles, with configurable
* priorities. There may be additional features but so far, no known Model 3
* games use them.
*
* VRAM is comprised of 1 MB for tile data and an additional 128 KB for the
* palette (each color occupies 32 bits). The four tilemap layers are referred
* to as: A (0), A' (1), B (2), and B' (3). Palette RAM may be located on a
* separate RAM IC.
*
* Registers
* ---------
0xF1180020: -------- -------- -------- -------- ?
-------- -------- x------- -------- Layer 3 bitdepth (0 = 8-bit, 1 = 4-bit)
-------- -------- -x------ -------- Layer 2 bitdepth (0 = 8-bit, 1 = 4-bit)
-------- -------- --x----- -------- Layer 1 bitdepth (0 = 8-bit, 1 = 4-bit)
-------- -------- ---x---- -------- Layer 0 bitdepth (0 = 8-bit, 1 = 4-bit)
-------- -------- ----x--- -------- Layer 3 priority (0 = below 3D, 1 = above 3D)
-------- -------- -----x-- -------- Layer 2 priority (0 = below 3D, 1 = above 3D)
-------- -------- ------x- -------- Layer 1 priority (0 = below 3D, 1 = above 3D)
-------- -------- -------x -------- Layer 0 priority (0 = below 3D, 1 = above 3D)
0xF1180040: Layer 0 & 1 modulation
-------- xxxxxxxx -------- -------- Red component
-------- -------- xxxxxxxx -------- Green component
-------- -------- -------- xxxxxxxx Blue component
0xF1180044: Layer 2 & 3 modulation
-------- xxxxxxxx -------- -------- Red component
-------- -------- xxxxxxxx -------- Green component
-------- -------- -------- xxxxxxxx Blue component
0xF1180060: x------- -------- -------- -------- Layer 0 enable
-------x xxxxxxxx -------- -------- Layer 0 Y scroll position
-------- -------- x------- -------- Layer 0 X line scroll enable
-------- -------- -------x xxxxxxxx Layer 0 X scroll position
0xF1180064: x------- -------- -------- -------- Layer 1 enable
-------x xxxxxxxx -------- -------- Layer 1 Y scroll position
-------- -------- x------- -------- Layer 1 X line scroll enable
-------- -------- -------x xxxxxxxx Layer 1 X scroll position
0xF1180068: x------- -------- -------- -------- Layer 2 enable
-------x xxxxxxxx -------- -------- Layer 2 Y scroll position
-------- -------- x------- -------- Layer 2 X line scroll enable
-------- -------- -------x xxxxxxxx Layer 2 X scroll position
0xF118006C: x------- -------- -------- -------- Layer 3 enable
-------x xxxxxxxx -------- -------- Layer 3 Y scroll position
-------- -------- x------- -------- Layer 3 X line scroll enable
-------- -------- -------x xxxxxxxx Layer 3 X scroll position
*
* VRAM Memory Map
* ---------------
*
* The lower 1 MB of VRAM is used for storing tiles, per-line horizontal scroll
* values, and the stencil mask, which determines which of each pair of layers
* is displayed on a given line and column.
*
* 00000-F5FFF Tile pattern data
* F6000-F63FF Layer A horizontal scroll table (512 lines)
* F6400-F67FF Layer A' horizontal scroll table
* F6800-F6BFF Layer B horizontal scroll table
* F6C00-F6FFF Layer B' horizontal scroll table
* F7000-F77FF Mask table (assuming 4 bytes per line, 512 lines)
* F7800-F7FFF ?
* F8000-F9FFF Layer A name table
* FA000-FBFFF Layer A' name table
* FC000-FDFFF Layer B name table
* FE000-FFFFF Layer B' name table
*
* Tiles may actually address the entire 1 MB space, although in practice,
* that would conflict with the other fixed memory regions.
*
* Palette
* -------
*
* The palette stores 32768 colors. Each entry is a little endian 32-bit word.
* The upper 16 bits are unused and the lower 16 bits contain the color:
*
* 15 0
* tbbb bbgg gggr rrrr
*
* The 't' bit is for transparency. When set, pixels of that color are
* transparent, unless they are the bottom-most layer.
*
* Tile Name Table and Pattern Layout
* ----------------------------------
*
* The name table is a 64x64 array of 16-bit words serving as indices for tile
* pattern data and the palette. The first 64 words correspond to the first
* row of tiles, the next 64 to the second row, etc. Although 64x64 entries
* describes a 512x512 pixel screen, only the upper-left 62x48 tiles are
* visible when the vertical and horizontal scroll values are 0. Scrolling
* moves the 496x384 pixel 'window' around, with individual wrapping of the
* two axes.
*
* The data is actually arranged in 32-bit chunks in little endian format, so
* that tiles 0, 1, 2, and 3 will be stored as 1, 0, 3, 2. Fetching two name
* table entries as a single 32-bit word places the left tile in the high 16
* bits and the right tile in the low 16 bits.
*
* The format of a name table entry in 4-bit color mode is:
*
* 15 0
* jkpp pppp pppp iiii
*
* The pattern index is '0ppp pppp pppi iiij'. Multiplying by 32 yields the
* offset in VRAM at which the tile pattern data is stored. Note that the MSB
* of the name table entry becomes the LSB of the pattern index. This allows
* for 32768 4-bit tile patterns, each occupying 32 bytes, which means the
* whole 1 MB VRAM space can be addressed.
*
* The 4-bit pattern data is stored as 8 32-bit words. Each word stores a row
* of 8 pixels:
*
* 31 0
* aaaa bbbb cccc dddd eeee ffff gggg hhhh
*
* 'a' is the left-most pixel data. These 4-bit values are combined with bits
* from the name table to form a palette index, which determines the final
* color. For example, for pixel 'a', the 15-bit color index is:
*
* 14 0
* kpp pppp pppp aaaa
*
* Note that index bits are re-used to form the palette index, meaning that
* the pattern address partly determines the color.
*
* In 8-bit color mode, the name table entry looks like:
*
* 15 0
* ?ppp pppp iiii iiii
*
* The low 15 'p' and 'i' bits together form the pattern index, which must be
* multiplied by 64 to get the offset. The pattern data now consists of 16 32-
* bit words, each containing four 8-bit pixels:
*
* 31 0
* aaaa aaaa bbbb bbbb cccc cccc dddd dddd
*
* 'a' is the left-most pixel. Each line is therefore comprised of two 32-bit
* words. The palette index for pixel 'a' is now formed from:
*
* 14 0
* ppp pppp aaaa aaaa
*
* Stencil Mask
* ------------
*
* For any pixel position, there are in fact only two visible layers, despite
* there being four defined layers. The layers are grouped in pairs: A (the
* 'primary' layer) and A' (the 'alternate') form one pair, and B and B' form
* the other. Only one of the primary or alternate layers from each group may
* be visible at a given position. The 'stencil mask' controls this.
*
* The mask table is a bit field organized into 512 (or 384?) lines with each
* bit controlling four columns (32 pixels). The mask does not appear to be
* affected by scrolling -- that is, it does not scroll with the underlying
* tiles, which do so independently. The mask remains fixed.
*
* Each mask entry is a little endian 32-bit word. The high 16 bits control
* A/A' and the low 16 bits control B/B'. Each word controls an entire line
* (32 pixels per bit, 512 pixels per 16-bit line mask, where the first 16
* pixels are allocated to the overscan region.) If a bit is set to 1, the
* pixel from the primary layer is used, otherwise the alternate layer is
* used when the mask is 0. It is important to remember that the layers may
* have been scrolled independently. The mask operates on the final resultant
* two pixels that are determined for each location.
*
* Example of a line mask:
*
* 31 15 0
* 0111 0000 0000 1111 0000 0000 1111 1111
*
* These settings would display layer A' for the first 32 pixels of the line,
* followed by layer A for the next 96 pixels, A' for the subsequent 256
* pixels, and A for the final 128 pixels. The first 256 pixels of the line
* would display layer B' and the second 256 pixels would be from layer B.
*
* The stencil mask does not affect layer priorities, which are managed
* separately regardless of mask settings.
*
* Scrolling
* ---------
*
* Each of the four layers can be scrolled independently. Vertical scroll
* values are stored in the appropriate scroll register and horizontal scroll
* values can be sourced either from the register (in which case the entire
* layer will be scrolled uniformly) or from a table in VRAM (which contains
* independent values for each line).
*
* The scroll registers are laid out as:
*
* 31 0
* e??? ???y yyyy yyyy h??? ??xx xxxx xxxx
*
* The 'e' bit enables the layer when set. The 'y' bits comprise a vertical
* scroll value in pixels. The 'x' bits form a horizontal scroll value. If 'h'
* is set, then the VRAM table (line-by-line scrolling) is used, otherwise the
* 'x' values are applied to every line. It is also possible that the scroll
* values use more or less bits, but probably no more than 1.
*
* Each line must be wrapped back to the beginning of the same line. Likewise,
* vertical scrolling wraps around back to the top of the tilemap.
*
* The horizontal scroll table is a series of 16-bit little endian words, one
* for each line beginning at 0. It appears all the values can be used for
* scrolling (no control bits have been observed). The number of bits actually
* used by the hardware is irrelevant -- wrapping has the effect of making
* higher order bits unimportant.
*
* Layer Priorities
* ----------------
*
* The layer control register (0x20) contains 4 bits that appear to control
* layer priorities. It is assumed that the 3D graphics, output by the Real3D
* pixel processors independently of the tile generator, constitute their own
* 'layer' and that the 2D tilemaps appear in front or behind. There may be a
* specific function for each priority bit or the field may be interpreted as a
* single 4-bit value denoting preset layer orders.
*
* Color Offsets
* -------------
*
* Color offsets can be applied to the final RGB color value of every pixel.
* This is used for effects such as fading to a certain color, lightning (Lost
* World), etc. The current best guess is that the two registers control each
* pair (A/A' and B/B') of layers. The format appears to be:
*
* 31 0
* ???? ???? rrrr rrrr gggg gggg bbbb bbbb
*
* Where 'r', 'g', and 'b' appear to be signed 8-bit color offsets. Because
* they exceed the color resolution of the palette, they must be scaled
* appropriately.
*
* Color offset registers are handled in TileGen.cpp. Two palettes are computed
* -- one for A/A' and another for B/B'. These are passed to the renderer.
*/
#include "Render2D.h"
#include "Supermodel.h"
#include "Shader.h"
#include "Shaders2D.h" // fragment and vertex shaders
#include "GLSLVersion.h"
/******************************************************************************
Frame Display Functions
******************************************************************************/
// Set up viewport and OpenGL state for 2D rendering (sets up blending function but disables blending)
void CRender2D::Setup2D(bool isBottom)
{
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); // alpha of 1.0 is opaque, 0 is transparent
// Disable Z-buffering
glDisable(GL_DEPTH_TEST);
// Clear everything if requested or just overscan areas for wide screen mode
if (isBottom)
{
if (m_aaTarget) {
glBindFramebuffer(GL_FRAMEBUFFER, m_aaTarget); // set target if needed
}
glClearColor(0.0, 0.0, 0.0, 0.0);
glViewport (0, 0, m_totalXPixels, m_totalYPixels);
glDisable (GL_SCISSOR_TEST); // scissor is enabled to fix the 2d/3d miss match problem
glClear (GL_COLOR_BUFFER_BIT); // we want to clear outside the scissored areas so must disable it
glEnable (GL_SCISSOR_TEST);
if (m_aaTarget) {
glBindFramebuffer(GL_FRAMEBUFFER, 0); // restore target if needed
}
}
// Set up the viewport and orthogonal projection
bool stretchBottom = m_config["WideBackground"].ValueAs() && isBottom;
if (!stretchBottom)
{
glViewport(m_xOffset - m_correction, m_yOffset + m_correction, m_xPixels, m_yPixels); //Preserve aspect ratio of tile layer by constraining and centering viewport
}
}
void CRender2D::DrawSurface(GLuint textureID)
{
if (m_aaTarget) {
glBindFramebuffer(GL_FRAMEBUFFER, m_aaTarget); // set target if needed
}
m_drawShader.EnableShader();
glEnable (GL_BLEND);
glBindVertexArray (m_vao);
glActiveTexture (GL_TEXTURE0); // texture unit 0
glBindTexture (GL_TEXTURE_2D, textureID);
glDrawArrays (GL_TRIANGLE_STRIP, 0, 4);
glBindVertexArray (0);
glDisable (GL_BLEND);
m_drawShader.DisableShader();
if (m_aaTarget) {
glBindFramebuffer(GL_FRAMEBUFFER, 0); // restore target if needed
}
}
void CRender2D::BeginFrame(void)
{
}
void CRender2D::PreRenderFrame(void)
{
glPixelStorei(GL_UNPACK_ROW_LENGTH, 512); // skip the non viewable data
for (int i = 0; i < 2; i++) {
if (!m_drawBuffers[i]) continue; // we don't have a draw buffer yet
glBindTexture(GL_TEXTURE_2D, m_textureIDs[i]);
glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 496, 384, GL_RGBA, GL_UNSIGNED_BYTE, m_drawBuffers[i]->data);
}
glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
}
void CRender2D::RenderFrameBottom(void)
{
Setup2D(true);
DrawSurface(m_textureIDs[0]);
}
void CRender2D::RenderFrameTop(void)
{
Setup2D(false);
DrawSurface(m_textureIDs[1]);
}
void CRender2D::EndFrame(void)
{
}
/******************************************************************************
Emulation Callbacks
******************************************************************************/
// Deprecated
void CRender2D::WriteVRAM(unsigned addr, uint32_t data)
{
}
/******************************************************************************
Configuration, Initialization, and Shutdown
******************************************************************************/
void CRender2D::AttachRegisters(const uint32_t* regPtr)
{
}
void CRender2D::AttachPalette(const uint32_t* palPtr[2])
{
}
void CRender2D::AttachVRAM(const uint8_t* vramPtr)
{
}
void CRender2D::AttachDrawBuffers(std::shared_ptr bottom, std::shared_ptr top)
{
m_drawBuffers[0] = bottom;
m_drawBuffers[1] = top;
}
Result CRender2D::Init(unsigned xOffset, unsigned yOffset, unsigned xRes, unsigned yRes, unsigned totalXRes, unsigned totalYRes, unsigned aaTarget, UpscaleMode upscaleMode)
{
// Resolution
m_xPixels = xRes;
m_yPixels = yRes;
m_xOffset = xOffset;
m_yOffset = yOffset;
m_totalXPixels = totalXRes;
m_totalYPixels = totalYRes;
m_correction = (UINT32)(((yRes / 384.) * 2.) + 0.5); // for some reason the 2d layer is 2 pixels off the 3D
m_aaTarget = aaTarget;
m_upscaleMode = (m_xPixels == 496 && m_yPixels == 384) ? UpscaleMode::Nearest : upscaleMode;
std::string um = "#define UPSCALEMODE " + std::to_string((int)m_upscaleMode) + '\n';
std::string version = Graphics::GLSLVersion::Get2D();
m_drawShader.LoadShaders((version + s_vertexShader).c_str(), (version + um + s_fragmentShader).c_str());
m_drawShader.GetUniformLocationMap("tex1");
// init uniform memory
m_drawShader.EnableShader();
glUniform1i(m_drawShader.uniformLocMap["tex1"], 0); // texture bound to texture unit 0
m_drawShader.DisableShader();
// allocate storage
for (auto& t : m_textureIDs) {
glBindTexture(GL_TEXTURE_2D, t);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, m_upscaleMode == UpscaleMode::Nearest ? GL_NEAREST : GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, m_upscaleMode == UpscaleMode::Nearest ? GL_NEAREST : GL_LINEAR);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 496, 384, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
}
return Result::OKAY;
}
CRender2D::CRender2D(const Util::Config::Node& config)
: m_config(config),
m_vao(0)
{
glGenVertexArrays(1, &m_vao);
glBindVertexArray(m_vao);
// no states needed since we do it in the shader
glBindVertexArray(0);
// create textures
glGenTextures(2, m_textureIDs);
}
CRender2D::~CRender2D(void)
{
if (m_vao) {
glDeleteVertexArrays(1, &m_vao);
m_vao = 0;
}
for (auto& t : m_textureIDs) {
glDeleteTextures(1, &t);
t = 0;
}
}