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Supermodel/Src/Graphics/Render2D.cpp

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/**
** Supermodel
** A Sega Model 3 Arcade Emulator.
** Copyright 2011 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 <http://www.gnu.org/licenses/>.
**/
/*
* Render2D.cpp
*
* To-Do List
* ----------
* - Fix color offsets: they should probably be applied to layers A/A' and B/B'
* rather than to the top and bottom surfaces (an artifact left over from
* when layer priorities were fixed as B/B' -> bottom, A/A' -> top). This can
* no longer be performed by the shaders, unfortunately, because of arbitrary
* layer priorities. Rather, three palettes should be maintained: master (the
* actual palette data), A, and B. Color offset writes should recompute
* these and the tile renderer should use either A or B palette (depending on
* the layer being drawn).
* - Is there a better way to handle the overscan regions in wide screen mode
* than using palette entry 0 as the fill color? Is clearing two thin
* viewports better than one big clear?
* - Layer priorities in Spikeout attract mode might not be totally correct.
* - 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.
*
* Implementation of the CRender2D class: OpenGL tile generator graphics.
*
* 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. 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.
*
* NOTE: Supermodel allocates 128 KB for the palette. Either this is incorrect
* (only 64 KB is needed to store 32K colors), the colors are inaccessible, or
* there is a way to access them but no game has done so yet. My suspicion is
* that the palette RAM is in fact only 64 KB but this needs to be verified by
* checking to see if any games write to the high 64 KB.
*
* Registers
* ---------
*
* Registers are listed by their byte offset in the PowerPC address space. Each
* is 32 bits wide and little endian. Only those registers relevant to
* rendering are listed here (see CTileGen for others).
*
* Offset: Description:
*
* 0x20 Layer configuration
* 0x40 Layer A/A' color offset
* 0x44 Layer B/B' color offset
* 0x60 Layer A scroll
* 0x64 Layer A' scroll
* 0x68 Layer B scroll
* 0x6C Layer B' scroll
*
* Layer configuration is formatted as:
*
* 31 0
* ???? ???? ???? ???? pqrs tuvw ???? ????
*
* Bits 'pqrs' control the color depth of layers B', B, A', and A,
* respectively. If set, the layer's pattern data is encoded as 4 bits,
* otherwise the pixels are 8 bits. Bits 'tuvw' form a 4-bit priority code. The
* other bits are unused or unknown.
*
* The remaining registers are described where appropriate further below.
*
* 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 16-bit word.
*
* The format of a palette word is:
*
* 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. Caveat: a bug in
* Scud Race's 'ROLLING START' animation may indicate this is either not
* strictly true or that the upper-left corner of the mask needs to be adjusted
* slightly. This bug has not been investigated thoroughly yet.
*
* 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). 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
* v??? ???y yyyy yyyy h??? ??xx xxxx xxxx
*
* 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. The
* meaning of 'v' is unknown. 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.
*/
#include <string.h>
#include "Pkgs/glew.h"
#include "Supermodel.h"
#include "Graphics/Shaders2D.h" // fragment and vertex shaders
/******************************************************************************
Definitions and Constants
******************************************************************************/
// Shader program files (for use in development builds only)
#define VERTEX_2D_SHADER_FILE "Src/Graphics/Vertex2D.glsl"
#define FRAGMENT_2D_SHADER_FILE "Src/Graphics/Fragment2D.glsl"
/******************************************************************************
Tile Drawing Functions
******************************************************************************/
// Draw 4-bit tile line, no clipping performed
void CRender2D::DrawTileLine4BitNoClip(UINT32 *buf, UINT16 tile, int tileLine)
{
unsigned tileOffset; // offset of tile pattern within VRAM
unsigned palette; // color palette bits obtained from tile
UINT32 pattern; // 8 pattern pixels fetched at once
// Tile pattern offset: each tile occupies 32 bytes when using 4-bit pixels
tileOffset = ((tile&0x3FFF)<<1) | ((tile>>15)&1);
tileOffset *= 32;
tileOffset /= 4; // VRAM is a UINT32 array
// Upper color bits; the lower 4 bits come from the tile pattern
palette = tile&0x7FF0;
// Draw 8 pixels
pattern = vram[tileOffset+tileLine];
*buf++ = pal[((pattern>>28)&0xF) | palette];
*buf++ = pal[((pattern>>24)&0xF) | palette];
*buf++ = pal[((pattern>>20)&0xF) | palette];
*buf++ = pal[((pattern>>16)&0xF) | palette];
*buf++ = pal[((pattern>>12)&0xF) | palette];
*buf++ = pal[((pattern>>8)&0xF) | palette];
*buf++ = pal[((pattern>>4)&0xF) | palette];
*buf++ = pal[((pattern>>0)&0xF) | palette];
}
// Draw 8-bit tile line, clipped at left edge
void CRender2D::DrawTileLine8BitNoClip(UINT32 *buf, UINT16 tile, int tileLine)
{
unsigned tileOffset; // offset of tile pattern within VRAM
unsigned palette; // color palette bits obtained from tile
UINT32 pattern; // 4 pattern pixels fetched at once
tileLine *= 2; // 8-bit pixels, each line is two words
// Tile pattern offset: each tile occupies 64 bytes when using 8-bit pixels
tileOffset = tile&0x3FFF;
tileOffset *= 64;
tileOffset /= 4;
// Upper color bits
palette = tile&0x7F00;
// Draw 4 pixels at a time
pattern = vram[tileOffset+tileLine];
*buf++ = pal[((pattern>>24)&0xFF) | palette];
*buf++ = pal[((pattern>>16)&0xFF) | palette];
*buf++ = pal[((pattern>>8)&0xFF) | palette];
*buf++ = pal[((pattern>>0)&0xFF) | palette];
pattern = vram[tileOffset+tileLine+1];
*buf++ = pal[((pattern>>24)&0xFF) | palette];
*buf++ = pal[((pattern>>16)&0xFF) | palette];
*buf++ = pal[((pattern>>8)&0xFF) | palette];
*buf++ = pal[((pattern>>0)&0xFF) | palette];
}
/******************************************************************************
Layer Rendering
******************************************************************************/
/*
* DrawLine():
*
* Draws a single scanline of single layer. Vertical (but not horizontal)
* scrolling is applied here.
*
* Parametes:
* dest Destination of 512-pixel output buffer to draw to.
* layerNum Layer number:
* 0 = Layer A (@ 0xF8000)
* 1 = Layer A' (@ 0xFA000)
* 2 = Layer B (@ 0xFC000)
* 3 = Layer B' (@ 0xFE000)
* y Line number (0-495).
* nameTableBase Pointer to VRAM name table (see above addresses)
* for this layer.
* hScrollTable Pointer to the line-by-line horizontal scroll value
* table for this layer.
*/
void CRender2D::DrawLine(UINT32 *dest, int layerNum, int y, const UINT16 *nameTableBase)
{
// Determine the layer color depth (4 or 8-bit pixels)
bool is4Bit = regs[0x20/4] & (1<<(12+layerNum));
// Compute offsets due to vertical scrolling
int vScroll = (regs[0x60/4+layerNum]>>16)&0x1FF;
const UINT16 *nameTable = &nameTableBase[(64*((y+vScroll)/8)) & 0xFFF]; // clamp to 64x64=0x1000
int vOffset = (y+vScroll)&7; // vertical pixel offset within 8x8 tile
// Render 512 pixels (64 tiles) w/out any horizontal scrolling or masking
if (is4Bit)
{
for (int tx = 0; tx < 64; tx += 4)
{
// Little endian: offsets 0,1,2,3 become 1,0,3,2
DrawTileLine4BitNoClip(dest, nameTable[1], vOffset); dest += 8;
DrawTileLine4BitNoClip(dest, nameTable[0], vOffset); dest += 8;
DrawTileLine4BitNoClip(dest, nameTable[3], vOffset); dest += 8;
DrawTileLine4BitNoClip(dest, nameTable[2], vOffset); dest += 8;
nameTable += 4; // next set of 4 tiles
}
}
else
{
for (int tx = 0; tx < 64; tx += 4)
{
DrawTileLine8BitNoClip(dest, nameTable[1], vOffset); dest += 8;
DrawTileLine8BitNoClip(dest, nameTable[0], vOffset); dest += 8;
DrawTileLine8BitNoClip(dest, nameTable[3], vOffset); dest += 8;
DrawTileLine8BitNoClip(dest, nameTable[2], vOffset); dest += 8;
nameTable += 4;
}
}
}
void CRender2D::MixLine(UINT32 *dest, const UINT32 *src, int layerNum, int y, bool isBottom)
{
/*
* Mix in the appropriate layer under control of the stencil mask, applying
* horizontal scrolling in theprocess
*/
// Line scroll table
const UINT16 *hScrollTable = (UINT16 *) &vram[(0xF6000+layerNum*0x400)/4];
// Load horizontal full-screen scroll values and scroll mode
int hFullScroll = regs[0x60/4+layerNum]&0x3FF;
bool lineScrollMode = regs[0x60/4+layerNum]&0x8000;
// Load horizontal scroll values
int hScroll;
if (lineScrollMode)
hScroll = hScrollTable[y];
else
hScroll = hFullScroll;
// Get correct offset into mask table
const UINT16 *maskTable = (UINT16 *) &vram[0xF7000/4];
maskTable += 2*y;
if (layerNum < 2) // little endian: layers A and A' use second word in each pair
++maskTable;
// Figure out what mask bit should be to mix in this layer
UINT16 doCopy;
if ((layerNum & 1)) // layers 1 and 3 are A' and B': alternates
doCopy = 0x0000; // if mask is clear, copy alternate layer
else
doCopy = 0x8000; // copy primary layer when mask is set
// Mix first 60 tiles (4 at a time)
UINT16 mask = *maskTable; // mask for this line (each bit covers 4 tiles)
int i = hScroll&511; // line index (where to copy from)
for (int tx = 0; tx < 60; tx += 4)
{
// If bottom layer, we can copy without worrying about transparency, and must also write blank values when this layer is not showing
//TODO: move this test outside of loop
if (isBottom)
{
// Only copy pixels if the mask bit is appropriate for this layer type
if ((mask&0x8000) == doCopy)
{
if (i <= (512-32)) // safe to use memcpy for fast blit?
{
memcpy(dest, &src[i], 32*sizeof(UINT32));
i += 32;
dest += 32;
}
else // slow copy, wrap line boundary
{
for (int k = 0; k < 32; k++)
{
i &= 511;
*dest++ = src[i++];
}
}
}
else
{
// Write blank pixels
memset(dest, 0, 32*sizeof(UINT32));
i += 32;
i &= 511; // wrap line boundaries
dest += 32;
}
}
else
{
// Copy while testing for transparencies
if ((mask&0x8000) == doCopy)
{
UINT32 p;
for (int k = 0; k < 32; k++)
{
i &= 511;
p = src[i++];
if ((p>>24) != 0) // opaque pixel, put it down
*dest = p;
dest++;
}
}
else
{
i += 32;
i &= 511;
dest += 32;
}
}
mask <<= 1;
}
// Mix last two tiles
if (isBottom)
{
if ((mask&0x8000) == doCopy)
{
for (int k = 0; k < 16; k++)
{
i &= 511;
*dest++ = src[i++];
}
}
else // clear
{
for (int k = 0; k < 16; k++)
{
i &= 511;
*dest++ = 0;
}
}
}
else
{
if ((mask&0x8000) == doCopy)
{
UINT32 p;
for (int k = 0; k < 16; k++)
{
i &= 511;
p = src[i++];
if ((p>>24) != 0)
*dest = p;
dest++;
}
}
}
}
void CRender2D::DrawTilemaps(UINT32 *destBottom, UINT32 *destTop)
{
// Base address of all 4 name tables
const UINT16 *nameTableBase[4];
nameTableBase[0] = (UINT16 *) &vram[(0xF8000+0*0x2000)/4]; // A
nameTableBase[1] = (UINT16 *) &vram[(0xF8000+1*0x2000)/4]; // A'
nameTableBase[2] = (UINT16 *) &vram[(0xF8000+2*0x2000)/4]; // B
nameTableBase[3] = (UINT16 *) &vram[(0xF8000+3*0x2000)/4]; // B'
// Render and mix each line
for (int y = 0; y < 384; y++)
{
// Draw each layer
DrawLine(lineBuffer[0], 0, y, nameTableBase[0]);
DrawLine(lineBuffer[1], 1, y, nameTableBase[1]);
DrawLine(lineBuffer[2], 2, y, nameTableBase[2]);
DrawLine(lineBuffer[3], 3, y, nameTableBase[3]);
//TODO: could probably further optimize: only have a single layer clear masked-out areas, then if alt. layer is being written to same place, don't bother worrying about transparencies if directly on top
// Combine according to priority settings
// NOTE: question mark indicates unobserved and therefore unknown
switch ((regs[0x20/4]>>8)&0xF)
{
case 0x5: // top: A, B, A'? bottom: B'
MixLine(destBottom, lineBuffer[3], 3, y, true);
MixLine(destTop, lineBuffer[2], 2, y, true);
MixLine(destTop, lineBuffer[0], 0, y, false);
MixLine(destTop, lineBuffer[1], 1, y, false);
break;
case 0x9: // ? all layers on top but relative order unknown (Spikeout Final Edition, after first boss)
memset(destBottom, 0, 496*sizeof(UINT32)); //TODO: use glClear(GL_COLOR_BUFFER_BIT) if there is no bottom layer
MixLine(destTop, lineBuffer[2], 2, y, true);
MixLine(destTop, lineBuffer[3], 3, y, false);
MixLine(destTop, lineBuffer[1], 1, y, false);
MixLine(destTop, lineBuffer[0], 0, y, false);
break;
case 0xF: // all on top
memset(destBottom, 0, 496*sizeof(UINT32)); //TODO: use glClear(GL_COLOR_BUFFER_BIT) if there is no bottom layer
MixLine(destTop, lineBuffer[2], 2, y, true);
MixLine(destTop, lineBuffer[3], 3, y, false);
MixLine(destTop, lineBuffer[0], 0, y, false);
MixLine(destTop, lineBuffer[1], 1, y, false);
break;
case 0x7: // top: A, B bottom: A'?, B'
MixLine(destBottom, lineBuffer[3], 3, y, true);
MixLine(destBottom, lineBuffer[1], 1, y, false);
MixLine(destTop, lineBuffer[2], 2, y, true);
MixLine(destTop, lineBuffer[0], 0, y, false);
break;
default: // unknown, use A and A' on top, B and B' on the bottom
MixLine(destBottom, lineBuffer[2], 2, y, true);
MixLine(destBottom, lineBuffer[3], 3, y, false);
MixLine(destTop, lineBuffer[0], 0, y, true);
MixLine(destTop, lineBuffer[1], 1, y, false);
break;
}
// Advance to next line in output surfaces
destBottom += 496;
destTop += 496;
}
}
/******************************************************************************
Frame Display Functions
******************************************************************************/
// Draws a surface to the screen (0 is top and 1 is bottom)
void CRender2D::DisplaySurface(int surface, GLfloat z)
{
// If bottom surface and wide screen, clear overscan areas
if (surface && g_Config.wideScreen)
{
UINT32 c = pal[0]; // just use palette color 0 for now (not the best solution, it's usually black)
GLfloat r = (GLfloat)(c&0xFF) / 255.0f;
GLfloat g = (GLfloat)((c>>8)&0xFF) / 255.0f;
GLfloat b = (GLfloat)((c>>16)&0xFF) / 255.0f;
glClearColor(r, g, b, 0.0);
glViewport(0, 0, xOffs, totalYPixels);
glClear(GL_COLOR_BUFFER_BIT);
glViewport(xOffs+xPixels, 0, totalXPixels, totalYPixels);
glClear(GL_COLOR_BUFFER_BIT);
}
// Set up the viewport and orthogonal projection
glViewport(xOffs, yOffs, xPixels, yPixels);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluOrtho2D(0.0, 1.0, 1.0, 0.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
// Draw the surface
glActiveTexture(GL_TEXTURE0); // texture unit 0
glBindTexture(GL_TEXTURE_2D, texID[surface]);
glBegin(GL_QUADS);
glTexCoord2f(0.0f/512.0f, 0.0f); glVertex3f(0.0f, 0.0f, z);
glTexCoord2f(496.0f/512.0f, 0.0f); glVertex3f(1.0f, 0.0f, z);
glTexCoord2f(496.0f/512.0f, 384.0f/512.0f); glVertex3f(1.0f, 1.0f, z);
glTexCoord2f(0.0f/512.0f, 384.0f/512.0f); glVertex3f(0.0f, 1.0f, z);
glEnd();
}
// Set up viewport and OpenGL state for 2D rendering (sets up blending function but disables blending)
void CRender2D::Setup2D(void)
{
// Enable texture mapping and blending
glEnable(GL_TEXTURE_2D);
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); // alpha of 1.0 is opaque, 0 is transparent
glDisable(GL_BLEND);
// Disable Z-buffering
glDisable(GL_DEPTH_TEST);
// Shader program
glUseProgram(shaderProgram);
}
// Convert color offset register data to RGB
void CRender2D::ColorOffset(GLfloat colorOffset[3], UINT32 reg)
{
INT8 ir, ig, ib;
ib = (reg>>16)&0xFF;
ig = (reg>>8)&0xFF;
ir = (reg>>0)&0xFF;
/*
* Uncertain how these should be interpreted. It appears to be signed,
* which means the values range from -128 to +127. The division by 128
* normalizes this to roughly -1,+1.
*/
colorOffset[0] = (GLfloat) ir * (1.0f/128.0f);
colorOffset[1] = (GLfloat) ig * (1.0f/128.0f);
colorOffset[2] = (GLfloat) ib * (1.0f/128.0f);
//printf("%08X -> %g,%g,%g\n", reg, colorOffset[2], colorOffset[1], colorOffset[0]);
}
// Bottom layers
void CRender2D::BeginFrame(void)
{
GLfloat colorOffset[3];
// Update all layers
DrawTilemaps(surfBottom, surfTop);
glActiveTexture(GL_TEXTURE0); // texture unit 0
glBindTexture(GL_TEXTURE_2D, texID[0]);
glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 496, 384, GL_RGBA, GL_UNSIGNED_BYTE, surfTop);
glBindTexture(GL_TEXTURE_2D, texID[1]);
glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 496, 384, GL_RGBA, GL_UNSIGNED_BYTE, surfBottom);
// Display bottom surface
Setup2D();
ColorOffset(colorOffset, regs[0x44/4]);
glUniform3fv(colorOffsetLoc, 1, colorOffset);
DisplaySurface(1, 0.0);
}
// Top layers
void CRender2D::EndFrame(void)
{
GLfloat colorOffset[3];
// Display top surface
Setup2D();
glEnable(GL_BLEND);
ColorOffset(colorOffset, regs[0x40/4]);
glUniform3fv(colorOffsetLoc, 1, colorOffset);
DisplaySurface(0, -0.5);
}
/******************************************************************************
Emulation Callbacks
******************************************************************************/
void CRender2D::WriteVRAM(unsigned addr, UINT32 data)
{
if (vram[addr/4] == data) // do nothing if no changes
return;
}
/******************************************************************************
Configuration, Initialization, and Shutdown
******************************************************************************/
void CRender2D::AttachRegisters(const UINT32 *regPtr)
{
regs = regPtr;
DebugLog("Render2D attached registers\n");
}
void CRender2D::AttachPalette(const UINT32 *palPtr)
{
pal = palPtr;
DebugLog("Render2D attached palette\n");
}
void CRender2D::AttachVRAM(const UINT8 *vramPtr)
{
vram = (UINT32 *) vramPtr;
DebugLog("Render2D attached VRAM\n");
}
// Memory pool and offsets within it
#define MEMORY_POOL_SIZE (2*512*384*4 + 4*512*4)
#define OFFSET_TOP_SURFACE 0 // 512*384*4 bytes
#define OFFSET_BOTTOM_SURFACE (512*384*4) // 512*384*4
#define OFFSET_LINE_BUFFERS (2*512*384*4) // 4*512*4 (4 lines)
bool CRender2D::Init(unsigned xOffset, unsigned yOffset, unsigned xRes, unsigned yRes, unsigned totalXRes, unsigned totalYRes)
{
float memSizeMB = (float)MEMORY_POOL_SIZE/(float)0x100000;
// Load shaders
if (OKAY != LoadShaderProgram(&shaderProgram,&vertexShader,&fragmentShader,NULL,NULL,vertexShaderSource,fragmentShaderSource))
return FAIL;
// Get locations of the uniforms
glUseProgram(shaderProgram); // bind program
textureMapLoc = glGetUniformLocation(shaderProgram, "textureMap");
glUniform1i(textureMapLoc,0); // attach it to texture unit 0
colorOffsetLoc = glGetUniformLocation(shaderProgram, "colorOffset");
// Allocate memory for layer surfaces
memoryPool = new(std::nothrow) UINT8[MEMORY_POOL_SIZE];
if (NULL == memoryPool)
return ErrorLog("Insufficient memory for tilemap surfaces (need %1.1f MB).", memSizeMB);
memset(memoryPool,0,MEMORY_POOL_SIZE); // clear textures
// Set up pointers to memory regions
surfTop = (UINT32 *) &memoryPool[OFFSET_TOP_SURFACE];
surfBottom = (UINT32 *) &memoryPool[OFFSET_BOTTOM_SURFACE];
for (int i = 0; i < 4; i++)
lineBuffer[i] = (UINT32 *) &memoryPool[OFFSET_LINE_BUFFERS + i*512*4];
// Resolution
xPixels = xRes;
yPixels = yRes;
xOffs = xOffset;
yOffs = yOffset;
totalXPixels = totalXRes;
totalYPixels = totalYRes;
// Create textures
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glGenTextures(2, texID);
for (int i = 0; i < 2; i++)
{
glActiveTexture(GL_TEXTURE0); // texture unit 0
glBindTexture(GL_TEXTURE_2D, texID[i]);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 512, 512, 0, GL_RGBA, GL_UNSIGNED_BYTE, surfTop);
if (glGetError() != GL_NO_ERROR)
return ErrorLog("OpenGL was unable to provide 512x512-texel texture maps for tilemap layers.");
}
DebugLog("Render2D initialized (allocated %1.1f MB)\n", memSizeMB);
return OKAY;
}
CRender2D::CRender2D(void)
{
xPixels = 496;
yPixels = 384;
xOffs = 0;
yOffs = 0;
memoryPool = NULL;
vram = NULL;
surfTop = NULL;
surfBottom = NULL;
for (int i = 0; i < 4; i++)
lineBuffer[i] = NULL;
DebugLog("Built Render2D\n");
}
CRender2D::~CRender2D(void)
{
DestroyShaderProgram(shaderProgram,vertexShader,fragmentShader);
glDeleteTextures(2, texID);
if (memoryPool != NULL)
{
delete [] memoryPool;
memoryPool = NULL;
}
vram = NULL;
surfTop = NULL;
surfBottom = NULL;
for (int i = 0; i < 4; i++)
lineBuffer[i] = NULL;
DebugLog("Destroyed Render2D\n");
}
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